CSV Nov09

In This Issue

In This Issue

In This Issue

Editor

MAHENDRA JAIN

Editor/Publisher is not responsible for views, data, figures etc. expressed in the articles by the authors.

—Editor

No part of this publication can be reproduced or transmitted in any form without the prior written permission from the publishers.

Edited, printed and published by Mahendra Jain for M/s. Pratiyogita Darpan, 2/11A, SwadeshiBima Nagar, AGRA–2 and printed by him at Pratiyogita Darpan Printing Unit, 5 & 6, Bye pass Road, Agra. Phone : 4053333, 2531101, 2530966 Fax

Daryaganj, New Delhi–110 002 Phone : 23251844/66 November 2009 Year—12 Issue—141

C.S.V.

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November

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2009

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1061

Regulars

Science and Technology 1065

Latest General Knowledge 1067

Inspiring Young Talents—

(i) Topper : Uttarakhand, PMT 2009 (4th Rank)

—Dhananjay Dwivedi 1071 (ii) CBSE (PMT) 2009 (54th Rank)—Garima Singh 1072

Science Tips 1074

Physics

Sound-III : Stationary Waves, Vibrations of Air Columns

and Stretched Strings 1076

Nuclear Physics-III : Nuclear Energy 1082

Typical Model Paper 1088

Typical Model Paper 1093

Chemistry

Nuclear Chemistry 1099

Typical Model Paper 1107

Typical Model Paper 1110

Typical Model Paper 1113

Zoology

Lymphatic System 1117

Biology and Therapy of Cancer 1122

Typical Model Paper 1126

Typical Model Paper 1128

Typical Model Paper 1131

Botany

Diversity of Life : Plant Groups 1134

Pollination 1140

Typical Model Paper 1143

Typical Model Paper 1146

Typical Model Paper 1149

Solved Paper : CBSE Medical Entrance Exam., 2009 1153

Other

Other

Other

Other

Other Features

Features

Features

Features

Features

Assertion and Reason Type Questions 1170

True or False 1173

Do You Know ? 1177

CSV Quiz Contest No. 138 1182

Correct Solution and Prize Winners of CSV Quiz No. 135 1184

To Our Readers

Dear Readers,

It is a matter of immense pleasure and great satisfaction to us in presenting to you the November issue of your favourite and frontline magazine ‘Competition

Science Vision’. PMT aspirants generally agree that the utility of each issue of the

magazine is unique and unbeaten. Its flawless presentation in all the subjects of premedical tests is its special quality rarely found in any other such magazine.

Our experienced authors are trying hard to make its each issue more and more examination-oriented including in it all the changes of examination pattern. This makes our readers updated for each year’s tests. We strive to make CSV to meet all your requirements.

Hard work under proper guidance is a must for success in any examination. Revision of what you have read is also necessary before you finally take up the examination. CSV is so designed that it provides you all you need for success.

Read CSV regularly and intelligently. It gives you the power to master your career and shape your destiny.

With best wishes for your success. Sincerely yours,

Mahendra Jain

(Editor)

C.S.V.

November

2009

1062

2009

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GHTS FOR THE MONTH

❥ Nature never did betray the heart that loved her. ❥ Do not jump on a man unless he’s down. ❥ Bottom is bottom even if it is turned upside down. ❥ Where wealth accumulates men decay.

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AWARDS/HONOURS

55th National Film Awards

Director Priyadarshan’s off-beat

Tamil Film ‘Kanjeevaram’ won the

best film award, 2007, while southern actor Prakash Raj has been adjusted as the best actor for his performance in the same film.

Renowned Malayalam film director Adoor Gopalakrishnan is selected as the best director for

‘Naalu Pennungal’ , while Kannada

actress Uma Shri is declared as the best actress for ‘Gulabi Takies’.

Bollywood star Aamir Khan’s directorial debut ‘Taare Zameen Par’

got the best family welfare award and Prasoon Joshi got the award for the best lyrics for ‘Maa’ a film about a

dyslexic child. Shankar Mahadevan received the National Award for the best playback singer. ‘Chak De India’

won the award for the best picture providing wholesome entertainment.

Sarswati Samman—Assamese

writer Lakshminandan Bora was honoured with the ‘Sarswati Samman 2008’ for his significant contributions

to Assamese literature.

Vyas Samman—Hindi writer

Mannu Bhandari was awarded the ‘Vyas Samman 2008’ for her invalu-able contributions to Hindi literature.

Sarswati Samman and Vyas Samman are given by K. K. Birla Foundation for promotion of Indian literature.

61st Annual Emmy Award 2009—Emmy Awards were given in

Los Angeles (U.S.A.) on September

21, 2009. 30 Rock and Mad Men

were the winners of every category.

30 Rock was named the best

comedy. Mad Men won the best

drama category. Toni Collette won the Emmy as the best actor in a comedy. Calenn Close won her second straight Emmy for best actress.

ICC Awards

England’s Ashes winning captain Andrew Strauss and Indian opener Gautam Gambhir are among the four players who were honoured with the ‘Cricketer of the Year Award’. India’s captain Mahendra Singh Dhoni and Australian fast bowler Mitchell Johnson are other cricketers who were honoured with the Awards by International Cricket Council in Johannesburg, South Africa, on October 1, 2009.

List of the awardees :

Cricketer of the Year—

Mahendra Singh Dhoni (Ind), Gautam Gambhir (Ind), Mitchell Johnson (Aus), Andrew Strauss (Eng).

Test Player of the Year—

Gautam Gambhir (Ind), Mitchell Johnson (Aus), Thilan Samaraweera (SL), Andrew Strauss (Eng).

One-Day Player of the Year—

Shivnarine Chanderpal (WI), MahendraSinghDhoni(Ind),Virender Sehwag (Ind), Yuvraj Singh (Ind).

Emerging Player of the Year—

BenHilfenhaus(Aus),GrahamOnions (Eng),JesseRyder (NZ), Peter Siddle (Aus).

Associate and Affiliate Player of the Year (non-Test nations)—

Rizwan Cheema (Can), Ryan ten Doeschate (Ned), William Porterfield (Irl), Edgar Schiferli (Ned).

Twenty-20 International Perfor-mance of the Year—Shahid Afridi

(Pak)-51 off 34 balls and two for 16 against South Africa in the World Twenty-20 semi-final in Nottingham on June 18.

Tillakaratne Dilshan (SL)-96 not outoff57ballsagainsttheWestIndies in the World Twenty-20 semi-final at the Oval on June 19.

Chris Gayle (WI)-88 off 50 balls againstAustraliainthe World Twenty-20 at the Oval on June 6.

Umar Gul (Pak)-5-6 against New Zealand in the World Twenty-20 at the Oval on June 13.

Women’s Cricketer on the Year—Charlotte Edwards (Eng),

Shelley Nitschke (Aus), Claire Taylor (Eng).

Umpire of the Year—Aleem Dar

(Pak), Tony Hill (NZ), Asad Rauf (Pak), Simon Taufel (Aus).

Spirit of Cricket

Award—Aus-tralia, England, New Zealand, Sri Lanka.

BOOKS

Civil Society and Human

Secu-rity—V. R. Raghavan (The volume

touches upon some very critical issues and raises many questions related to human security).

Jammu and Kashmir : The

Cold War and the West—D. N.

Panigrahi—(In this book the author

shows that the Western support to Pakistan played a key role in shaping the India-Pakistan contestation on Jammu and Kashmir. The military anddiplomaticassistancetoPakistan, sustained its long-running offensive to take control of the state.)

Reducing Global Poverty : Patterns of Potential Human

Pro-gress—Bary B. Hughes (This hefty

work, the first in a series of annual volumes, deals with poverty reduction issues).

The Corporate Greenhouse—

Yda Schreuder (The book discusses

the role of MNCs in shaping the implementation of climate change agreements).

DAYS

October 1—International Day for

Elderly.

October 2—Gandhi Jayanti, Lal

Bahadur Shastri’s Jayanti, World Vegetation Day.

October 3—World Habitat Day. October 4—World Animal

Wel-fare Day.

October 9—World Post Office

Day.

October 11—World Allergy

Awareness Day.

October 13—UN International

Day for Natural Disaster Reduction.

October 14—World Standards

Day.

October 15—World Sight Day

(Second Thursday of October), World White Cane Day (Guiding the Blind).

October 16—World Food Day. October 21—Police

Commemo-ration Day.

October 24—U.N. Day, World

Development Information Day.

October 27—Infants Day. October 30—World Thrift Day.

October31—NationalIntegration

Day.

Y. S. R. Reddy (A Talented

leader)—In the heart-rending tragedy

of Yeduguri Sandinti

RajasekharaReddy’s

demise in a heli-copter crash, Andhra Pradesh has lost its most charismatic leader and the Con-gress its most politi-cally talented and resourceful Chief Minister. A medical

Yeduguri Sandinti Rajasekhara

Reddy

graduate, YSR, as he was widely known, was a politician of Pulivendula in Kadapa district. He became an MLA at the age of 29, a Minister two

years later, and never lost an Assembly or Lok Sabha election thereafter. A devout Christian, he made pilgrimages to Bethlehem and Tirumala with equal piety, showing his broad mindedness.

The game-changing event was his 1500 km padayatra in 2003, which brilliantly tapped into mass unrest over the agrarian crisis and captured him to the seat of power a year later. He tirelessly presented his mission as the transformation of agriculture and farmers’ lives and the ending of agrarian distress. His ‘Jilayagnam’ drive to irrigate ten million acres of land by 2014, his Agriculture Tech-nology Mission, his vigorous imple-mentation and expansion of the National Rural Employment Guar-antee Scheme and his schemes to supply rice at Rs. 2 per kg. to the poor and provide free power to farmers, won his enormous credibility on the ground.

Norman Borlaug—Dr. Norman

Borlaug, who passed away in Dallas, Texas on September 13, 2009 at the age of 95, remains the only recipient of the Nobel Prize for agriculture, specifically the Peace prize of 1970. Possessed of insatiable curiosity about matters, botanical and blessed with remarkable energy and scientific incisiveness, Dr. Borlaug worked in Mexico in 1950s, where he crossbred a ‘dwarf’ strain of wheat. This, when treated with chemical fertilizers and pesticides, produced for greater quantities of seeds than the earlier varieties had done. His discovery was commercially introduced in Mexico in

1956, and the 1963 harvest was six times greater than that of 1956.

An Assault on Hunger : Norman E. Borlaug and his wife Margaret with the

Nobel Peace Prize he was awarded in 1970

Dr. Borlaug had a special place in the hearts of all Indians as he, alongwith M. S. Swaminathan,brought the ‘Green Revolution’ in India mark-ing a watershed in India’s agrarian economy and rural development.

At a time in sixties when India was facing the spectre of severe food shortages, his introduction of high yielding varieties of (wheat) seeds set in motion a technological revolution in Indian agriculture that led eventually to the country achieving self-suffi-ciency in food grains. ‘Green Revolu-tion’ lifted the spirits of Indian people and gave them new hope and con-fidence. He was the father of ‘Green Revolution’ in India. The ‘grateful nation’ mourns his death and owes a debt of gratitude to this greatman.

This greatest hunger-fighter for all time, made a profound difference to the lives of hundreds of millions of people in developing world.

Raj Singh Dungarpur—The

former President of the Board of Control for Cricket in India (BCCI), Raj Singh Dungarpur (73), passed away in Mumbai on September 12, 2009 after prolonged illness. He had been suffering from alzheimer and did not recognise his acquaintances. He was the third son of the former ruler of Dungarpur, Maharawal Lakshman Singhji. He graduated from Vikram University, Ujjain.

He was an excellent cricketer and played for Rajasthan in Ranji Trophy and other national tourna-ments for 16 years, as a medium fast bowler. He took 206 wickets and

scored 1292 runs in national tourna-ments. He worked as the national selector for two terms. He was the founder-Chairman of National Cricket Academy, Bangalore.

V. K. Sarswat (New D.G.,

DRDO)—Dr. V.K. Sarswat assumed

office as the Director-General of the Defence Research and Development Organisation (DRDO) and Scientific Advisor to the Ministry of Defence. He wouldalsobetheSecretaryof Depart-ment of Defence Research and Development in the Ministry of Defence. He succeeded Dr. M. Natarajan who retired. Earlier Dr. Sarswat had been Chief Controller, Research and Development (Missiles and Strategic Systems), DRDO.

Dr. Sarswat, who has a Ph. D. degree in combustion engineering, joined DRDO in 1972. He led the development of India’s tactical and strategic missile systems and anti-missile systems.

K. Rosaiah (New C.M., A.P.)—

Mr. K. Rosaiah (76), the seniormost member in Y.S. Rajasekhara cabinet, was sworn-in as the new Chief Minis-ter of Andhra Pradesh. The State Governor Mr. N. D. Tiwari adminis-tered the oath of office collectively to all the 34 members of Y. S. Rajasekhara Reddy cabinet also. Mr. Rosaiah had been a member of several Congress cabinets in the past.

Irina Bokova (First Woman to

Head UNESCO)—In what can only

be described as a stunning upset. IrinaBokova,Bulgaria’sformerforeign minister and currently ambassador to Paris, became the first woman to head UNESCO, the Paris-based United Nations’ agency for education, science and culture. Ms. Bokova was elected on September 23, 2009 by the Organisation’s 58-member Executive Board winning 31 votes to defeat her rival, Egypt’s Culture Minister, Farukh Hosni, who polled 27.

Mr. Bokova also became the first person from the former Soviet bloc countries to be elected to this post.

Y. Hatoyama (New P. M.,

Japan)—Mr. Yukio Hatoyama, on

September 16, 2009, was appointed as Japan’s 93rd Prime Minister following his party’s landslide victory in the August 30 general election. Mr. Hatoyama was

appointed as Prime Yukio Hatoyama

Minister at the plenary session of both the House of Representatives and the House of Councillors. He is theleaderofCentre-leftcoalition.With his assumption of office, the curtain came down over a half-century of conservative rule in Japan.

Mr. Hatoyama’s agenda is spark-ing a previously unthinkable idea that the U. S. may have to exit from the centre-stage of the next big theatre in global affairs.

Somdev Devvarman (Davis Cup

Hero)—Somdev Devvarman scripted

a spectacular win over South Africa’s Rik-de-Voest in a high-voltage marathan five-setter to put Indiaback

Somdev Devvarman

in the elite Davis Cup World Group after a gap of 11 years, on Septem-ber 20, 2009 in Johannesburg (South Africa). The tenacious Somdev won 3–6, 6–7 (3), 7–6 (5), 6–2, 6–4 after an energy-sapping battle of four hours and 38 minutes at the Ellis Park indoor stadium. Down by two sets, Somdev made an incredible comeback as he overcame an early break of serve to break back de-voest in the fourth game. Somdev wrapped up the set in the eighth game and it all boiled down to the fifth and decisive set.

This win of Davis Cup gave India an unassailable 3–1 lead over the Rainbow Nation.

Kochi (The longest rail-bridge)—

Engineers in Kochi (Kerala) are giving

final touches to the 4·62 km long rail bridge connecting the mainland to the

● The structure has a clearance of 7m above water and is made of 1 3 4 pillars.

● About 18,000 tonnes of cement and 50,000 metric tonnes of steel have gone into the structure.

● The initial cost was estimated to be Rs. 246 cr, which was later revised to Rs. 298 cr.

proposed international container trans-shipment terminal on Vallar-padam island across the Vembanad lake in Ernakulam district. Due to be commissioned in November 2009, it will be the longest rail bridge in India. Currently, the record is held by the Nehru Sethu near Dehri-on-Sone, located on the Kolkata-Delhi line. The Nehru Sethu is 3·065 km-long.

This bridge is expected to save exporters of crores of rupees wasted in trans-shipment of their goods through other ports. The project is also set to transform the industrial environment in the State.

SPORTS

Cricket

Squads for Irani Trophy and Champions League—Cricket

matches between Ranji Champion, Mumbai and rest of India for the Irani Trophy will be held at Nagpur during October 1 till 5. Squads for the rest of India for Irani Trophy and Challenger Series are—

Irani Trophy : Rest of India—

Gautam Gambhir (Capt.), S. Badri-nath (Vice-Capt.), M. Vijay, Virat Kohli, Manoj Tiwary, Ravindra Jadeja, Irfan Pathan, Wriddiman Saha, S. Sreesanth, Munaf Patel, Pragyan Ojha, Kedar Jadhav, Abhinav Mukund, Uday Kaul and Sudeep Tyagi.

ChallengerSeries:IndiaBlue—

M. S. Dhoni (Capt.), Sachin Ten-dulkar, Wasim Jaffer, Jalaj Saxena, Suresh Kumar, Kedar Jadhav, Abhishek Nayar, Yusuf Pathan, Naman Ojha, Harbhajan Singh, S. K. Trivedi, S. Sreesanth, Ashok Dinda and A. S. Goswami.

India Red—Yuvraj Singh (Capt.),

M. Vijay, Sunny Sohail, Shikhar Dhawan, Ishant Jaggi, Ravindra

Jedeja, Bhuvneshwar Kumar, Wriddi-man Saha, R. Ashwin, Sudeep Tyagi, Munaf Patel, S. S. Tiwary, Ishant Sharma and H. Khadiwale.

India Green—Suresh Raina

(Capt.), A. Rahane, Tanmay Srivast-ava,RaviInderSingh, Manoj Tiwary, S. Badrinath, Chetanya Nanda, Irfan Pathan, Parthiv Patel, S. K. Jakati, L. Balaji, Dhawal Kulkarni, Pankaj Singh and Uday Kaul.

ICC Champions Trophy 2009—

ICC Champions Trophy Tournament started on September 22, 2009 in South Africa and final will be played on October 5, 2009.

ICC Champions Trophy 2009 Schedule

Group A : Australia, India, Pakistan and West Indies.

Group B : England, New Zealand, South Africa and Sri Lanka

Oct. 2 Ist Semifinal (A1 Vs. B2)

Centurion Oct. 3 2nd Semifinal

(B1 Vs. A2)

Johannesburg Oct. 5 Final Centurion

India Wins Compaq Cup—

Sachin Tendulkar’s century, Har-bhajan Singh’s five-wicket haul and the magnitude of the target (320 in 50 overs) ensured that India won the Compaq Cup final against Sri Lanka in Colombo on September 15, 2009. Sachin Tendulkar held centre stage at the Premdasa Stadium. His 44th ODI century—his fourth at this ground and his sixth in tournament finals— helped India to score 319 for five in 50 overs in the championship match for the Compaq Cup.

Tennis

U. S. Open—India’s Leander

Paes and Czech Republic’s Lucas Dlouhy won the U. S. open men’s doubles title defeating India’s Mahesh Bhupathi and Mark Knowles of Bahamas 3–6, 6–3, 6–2 in New York on September 14, 2009. This was Paes’ 10th Grand Slam title, including six men’s doubles and four mixed doubles crown.

The Results

Prefix denotes seeding Women Singles Final : Kim Clijsters (Bel) bt 9-Caroline Wozniacki (Den) 7–5, 6–3.

Men Singles Final : 6-Juan Martin del Potro (Arg) bt 1-Roger Federer (Sui) 3–6, 7–6(5), 4–6, 7–6(4), 6–2.

Women Doubles : 4-Serena Williams & Venus Williams (USA) bt 1-Cara Black (Zim) and Liezel Huber (USA) 6–2, 6–2.

Men Doubles Final : 4-Leander Paes (Ind) & Lukas Dlouhy (Cze) bt 3-Mahesh Bhupathi (Ind) & Mark Knowles (Bah) 3–6, 6–3, 6–2.

Junior Singles Boys Final : 3-Bernard Tomic (Aus) bt Chase Buchanan (USA) 6–1, 6–3.

Girls Final : 11-Heather Watson (GBr) bt Yana Buchina (Rus) 6–4, 6–1.

Billiards

IBSF World Professional Billiards Championship—India’s

Pankaj Advani is 2009 World

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‘‘Hardwork, motivation and encouragement of family members and

positive thinking are the main elements of my success in this

examination.’’

—Dhananjay Dwivedi

Topper—Uttarakhand, PMT–2009 (4th Rank)

[‘Competition Science Vision’ arranged an exclusive interview with Mr. Dhananjay Dwivedi who has

the credit of securing a high position in the list of successful candidates of Uttarakhand PMT, 2009. For his

brilliant success he deserves all praise and our heartiest congratulations. This important interview is

presented here in its original form.]

CSV—Congratulations on your

brilliant success.

Dhananjay—Thanks.

CSV—Before knowingyour result

what did you think about those who achieve top positions ?

Dhananjay—They are like us but

do things differently.

CSV—Achieving top position has

come as surprise to you or were you confident of achieving it ?

Dhananjay—Not so good but I

was sure that blessings of my parents and teachers will not fail so I was expecting under 50th rank.

CSV—What do you think is the

secret of your success ?

Dhananjay—My parents and my

Bhaiya-Bhabhi’s motivating behaviour which never demoralised me.

CSV—In how many attempts did

you get this success ?

Dhananjay—It was my 3rd

attempt.

CSV—What were the

shortcom-ings in your preparation for earlier attempts ? How did you make up for them this time ?

Dhananjay—I was weak in

Biology. But this time my teachers and friends supported me very much so I got a position in it also.

CSV—From where did you get

the inspiration of choosing a medical career ?

Dhananjay—My father and

mother.

CSV—From when did you start

the preparation for it ?

Dhananjay—Just after 12th but I

think it must be right from the 11th standard to achieve good success in less time.

CSV—What planning did you

make for preparation ? Please tell something in detail.

Dhananjay—From the beginning

of this year, I planned to take more and more tests, particularly of objec-tive questions in which material of CSV, helped me a lot.

—CompetitionScienceVision is a landmark in the field of science magazines for pre-medi-cal examinations. It gives all important facts with easily under-standable short explanations.

—Dhananjay Dwivedi

CSV—How much time did you

devotedaily and regularly for Physics, Chemistry, Zoology and Botany ?

Dhananjay—Initially, in my first

year of preparation, I give almost one hour for each subject, but in my last year I always gave more time on my weak points. Subject not mattering much.

CSV—Out of the above four

subjects,towhich subject did you give more weightage and why ?

Dhananjay—Certainly Biology

because firstly we are going to become doctor and the almost in every entrance exam there are more questions on Biology. But Chemistry is very scoring subject.

CSV—Did you make complete

study of alltopics or of some selective topics ?

Dhananjay—I always stress

more on those points which my teachers tell me because being selec-tive is also the key to success. Don’t waste time in vain for the less weightage portion.

CSV—How did you give final

touches to your preparation ?

Dhananjay—After preparing, I

joined one month test series which was helpful for whole revision and discussion with the teachers and classmates was utmost important.

CSV—Did you prepare notes ? Dhananjay—Yes, I prepared

notes buttheywerevery selective and shortwhichcanbestudied at the night before the examination and without tension.

CSV—What was your attitude for

solving numerical questions ? What weightage did you give them ?

Dhananjay—One must

concen-trate on numericals sincerely because in medical exams they are generally formula based so we can score good marks in them.

Bio-Data

Name—Dhananjay Dwivedi Father’s Name—Sri Brij Bhushan

Dwivedi

Mother’s Name—Smt. Shakuntla

Dwivedi

Educational Qualifications— H. S. / Std. X—89·4% (P.P.J.

Saraswati Vihar, Nainital), 2004.

Inter/Std. XII—76% (P.P.J.

Saras-wati Vihar, Nainital), 2006.

CSV—How much time is

suffi-cient for preparing for this examina-tion ?

Dhananjay—Actually planning is

very important because upto my 12th class I had not planned my career so I got this success late but I think two years are sufficient.

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⎯ Inspiring Young Talent ⎯

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‘‘Sustained and scheduled study with guidance of teachers is the

secret of my success.’’

—Garima Singh

CBSE (PMT) 2009 [General Rank-54, OBC Rank-5]

[‘Competition Science Vision’ arranged an exclusive interview with Miss Garima Singh who has the

credit of being successful in CBSE (PMT) and U.P.-CPMT with high ranks. For her brilliant success, she

deserves all praise and our heartiest congratulations. This important interview is presented here in its

original form.]

CSV—Congratulations on your

brilliant success.

Garima—Thank you, Sir.

CSV—Before knowingyour result

what did you think about those who achieve top positions ?

Garima—I thought they must be

some extraordinary persons, much more studious than myself.

CSV—Achieving top position has

come as surprise to you or were you confident of achieving it ?

Garima—I was confident of

achieving good rank but was not sure about such high rank.

CSV—What do you think is the

secret of your success ?

Garima—I think sustained and

scheduled study is the secret of my success along with the guidance of the teachers.

CSV—In how many attempts did

you get this success ?

Garima—It was my second

attempt.

CSV—What were the

shortcom-ings in your preparation for earlier attempts ? How did you make up for them this time ?

Garima—I was not so much

serious about my study in the first attempt as in second attempt.

CSV—From where did you get

the inspiration of choosing a medical career ?

Garima—My mother always told

me that for girls the most respectable job is to be a doctor.

CSV—From when did you start

the preparation for it ?

Garima—After class X.

CSV—What planning did you

make for preparation ? Please tell something in detail.

Garima—I used to make a time

table nearly daily for what to do that

day. I used to decide subject matters to study for the day and sleep only after completing them.

—CSVisanicemagazine and is very useful for pre-medical examinations. It contains good subjectmatterandquality sample questionsinexhaustivenumbers.

—Garima Singh

CSV—How much time did you

devotedaily and regularly for Physics, Chemistry, Zoology and Botany ?

Garima—After 6 hours of

coaching, I devoted 7-8 hours daily for self study.

CSV—Out of the above four

subjects,towhich subject did you give more weightage and why ?

Garima—I gave weightage to the

subjects according to the toughness of the lesson which I am going to read. If it is from Physics then more weightage for it and if from Botany then less for it.

CSV—Did you make complete

study of alltopics or of some selective topics ?

Garima—I tried to make

com-plete study of all subjects.

CSV—How did you give final

touches to your preparation ?

Garima—After reading the

lessons, I go to the lesson content at start and used to make ticks for what I know I studied. This gave me confi-dence.

CSV—Did you prepare notes ? Garima—Yes, I prepared short

but comprehensive notes.

CSV—What was your attitude for

solving numerical questions ? What weightage did you give them ?

Garima—They are very

impor-tant. In PMT’s, the numericals are generally net very tough and they assure easy marks. If any numerical was very long then I solved it at last.

CSV—How much time is

suffi-cient for preparing for this examina-tion ?

Garima—Two years of deep

study is sufficient.

CSV—From what level of

educa-tion should an aspirant begin pre-paring for it ?

Garima—From class XI.

Bio-Data

Name—Garima Singh

Father’sName—SriDharmrajSingh

Mother’s Name—Smt. Renu Singh Educational Qualifications— H.S./Std. X—90% (Kendriya

Vidyalaya, DLW), 2006.

Inter/Std. XII—89·8% (Kendriya

Vidyalaya, DLW), 2008.

Special Ahievements—

● Also selected in CPMT, 2009 ● Selected in National Science

Exhibition (KVS), 2007

● Got 3rd District Rank in Maths

Olympiad one time

CSV—What was your order of

preference for various branches for which this test is held ?

Garima—Only MBBS.

CSV—Please mention various

books in each subject and magazines on which you based your preparation.

Garima—NCERT Booksfor each

subject. Elementary Biology, ABC Chemistry, Pradeep Physics, H. C. Verma for Physics and CSV maga-zine.

CSV—Did you take coaching in

your preparation ?

Garima—Yes, I took JRS

Tuto-rials, Varanasi. It was very useful. I was much influenced by its Director Sir A. K. Jha. He gave equal attention to each student and taught every topic in a playing manner.

CSV—What help do the science

magazines render in the preparations for this examination ?

Garima—Theygive extra edge in

preparations and provide knowledge in some currently discovered matters related to our subject topics.

CSV—What will be your criterion

for selecting a magazine for these examinations ?

Garima—It must have

correct-ness in its writings and should explain difficult things in easy way.

Personal Qualities

Hobbies—Listening songs and

playing cricket

Ideal Person—My mother Strong Point—My confidence Weak Point—Being nervous at

some events

CSV—Whatis your opinion about

our Competition Science Vision ? How much helpful and useful do you find it ?

Garima—It is a nice magazine. It

contains subject matter and sample questions in good amount.

CSV—Please suggest in what

way CSV can be made more useful for medical aspirants.

Garima—It is already very useful

and can be made more useful by introducing more diagrams alongwith questions.

CSV—Please mention your

posi-tion in the merit list as well as the marks obtained in different subjects. Whatwereyouraggregatepercentage of mraks ?

Garima—Iobtained All India rank

5 in OBC category and 54th All India General rank. In Physics and Chemistry together I got 66/100. In Botany and Zoology I got 78/100 in CBSE Mains subjective examination.

CSV—What books/magazines/

newspapers did you read for G.K. preparations ?

Garima—I hadn’t read any

specific book for G.K. I got it from the Internet, Dainik Jagran, The Times of India and CSV magazine.

CSV—Whom would you like to

give credit for your success ?

Garima—First my parents, then

to my teachers and then myself.

CSV—Please tell us something

about your family.

Garima—My father is a Senior

Section Engineer in DLW. My mother is an architect Engineer. I have a sister and a brother who are younger to me.

CSV—What in your frank opinion

has been the biggest mistake in your preparation for this test ?

Garima—I don’t find any big

mistake.

CSV—What message would you

like to give for our readers of CSV ?

Garima—They must try to get

their dreams with whole heart, mind and soul taken together they will surely be get success.

Physics

1. For wattless current what should be the value of the power factor of the circuit ?

➠

2. For which colour is the critical angle of light, passing from glass to air, minimum ?

➠

3. Give an example of application of mutual induction in any device.

➠

4. What is the correct sequence of the semiconductors silicon, tellunium and germanium in the increasing order of their energy gap ?

➠

5. Which ammeter is used to measure alternating current ?

➠

6. What quantity has the ampere-second as its unit ?

➠

7. By seeing a glowing electric bulb can you say if it is being fed by A.C. or D.C.

➠

8. Whatdoes the sudden burst of a cycletyrerepresent?

➠

9. What happens to the velocity and wavelength of light when it enters a denser medium ?

➠

10. The skylab space station did not have a safe landing. Why ?

➠

11. What happens when even a small bird hits a flying aeroplane ?

➠

12. When does the lunar eclopse occur ?

➠

moon and the sun

13. Why is the cooling inside a refrigerator not proper when a thick layer of ice deposits on the freezer ?

➠

14. Which type of computer is often found in small business and in homes and classrooms ?

➠

least costly type of computer

15. Out of joule, calorie, kilowatt and electron-volt which one is not the unit of energy ?

➠

16. How does the atmospheric pressure vary with height?

➠

h above sea level. For an ‘ideal’ atmosphere at

constant temperature P = P₀e– kh where k is a

constant and P₀ is the pressure at the surface

17. How is r.m.s. velocity of gas molecules related to absolute temperature of the gas ?

➠

18. What are transducers ?

➠

another (e.g. sound to electrical) are called

transducers

19. Is polarisation the property of all types of waves ?

➠

➠

and vice-versa

Chemistry

21. What is Turnbull's blue ?

➠

22. An hypothesis tested by experiments is known as

➠

23. What is magnesia alba ?

➠

(used as an antacid) 24. The humidity of air is measured by

➠

25. What is oleum ?

➠

Also known as fuming sulphuric acid

26. Vulcanised rubber was invented by

➠

27. An amino acid which does not contain a chiral

centre.

➠

28. Scientist who perfected the technique for converting pig iron into steel

➠

29. When the pH of the blood is lower than the normal value, this condition is known as

➠

30. The electrolytic method of obtaining aluminium from bauxite was first developed by

➠

31. Which compound possesses characteristic smell like that of mustard oil ?

32. First solar bettery was developed in the

➠

33. What is Wilkinson's catalyst ?

➠

[RhCl (PPh₃)₃]

34. In 1836 the galvanised iron was introduced first in

➠

35. What is caro's acid ?

➠

36. A porcelain funnel used for filtration by suction is known as

➠

37. What is diazomethane ?

➠

38. A drying chamber, containing chemicals such as concentrated sulphuric acid or silica gel is known as

➠

39. Reforming of a gasoline fraction to increase bran-ching in presence of AlCl₃ is known as

➠

40. A condenser consisting of glass tube surrounded by another glass tube through which cooling water flows is known as

➠

Zoology

41. The earliest prokaryotes must have been

➠

42. Which ions are most concentrated outside a resting neuron ?

➠

43. The only arthropods with two pairs of antennae are the

➠

44. Which type of cartilage is present in rib cage and the tip of nose ?

➠

45. Most fossils are found in

➠

46. Where the Meissner’s corpuscles and Merkel’s disks are located ?

➠

47. To make a karyotype, chromosomes are photogra-phed during

➠

48. Which kind of glands have possible role in communi-cation as scent glands ?

➠

49. Viruses are obligate parasites of

➠

50. Which kind of bone marrow is present in the interior of each epiphysis ?

➠

51. Lack of precision with regard to the third base in codon and anticodon is the

➠

52. What is called the air spaces present in some of cranial and facial bones ?

➠

53. The basic monomers used in DNA replication are

➠

54. What is called the smallest strength of stimulus that causes muscle contraction ?

➠

55. The form of endocytosis in which specific molecules bind to receptor sites on the external surface of the membrane is called

➠

56. Where the osteocytes of compact bone are orga-nized?

➠

57. The term humour refers to

➠

58. What is gradually lost from bones during aging ?

➠

59. Most vitamins function as

➠

60. Which enzyme from small intestinal mucosa digests maltose and sucrose ?

➠

Botany

61. What are nonseptate fungal hyphae ?

➠

62. What is alternation of sexual and asexual reproduc-tion in the life cycle of plants called ?

➠

63. Why does distinguishing species on the basis of reproductive isolation run into problems ?

➠

reproductive isolation is very difficult to observe

64. What is a catalytically active complex made up of an apoenzyme and a coenzyme called ?

➠

65. What does retrovirus have ?

➠

that have a DNA stage

66. What is the first stable product of photosynthesis in C₄ plants ?

➠

67. What is the chief means of achieving genetic variation ?

➠

C.S.V.

November

2009

1076

Stationary Waves

(i) When two progressive waves of equal wavelength and amplitude moving in opposite directions in a medium with the same speed superpose on each other, a new wave is formed that does not seem to proceed in any direction. Such a wave is called the stationary wave.

(ii) A stationary wave does not transmit energy in the medium.

Important

Let the wave moving in positive x-direction be represented by

y₁ = a sin 2π λ (vt –x)

and the wave moving in negative x-direction be given by

y2 = a sin 2π_λ (vt + x)

Then the resultant wave due to superposition is given by

y = y₁ + y₂ = 2a cos 2πx λ sin 2πvt λ = A sin 2πvt λ

(iii) The amplitude of the stationary wave is given by

A = 2a cos 2πx λ

(iv) The points where the amplitude of the resultant wave is maximum are called the antinodes. For anti-nodes x = 0, λ 2 , λ, 3λ 2 , …… and A = ± 2a.

(v) The points where the amplitude of the resultant wave is minimum are called the nodes. For nodes

x = λ₄ , 3λ₄ , 5λ₄ , ……

and A = 0.

(vi) The distance between two consecutive nodes or antinodes is λ/2.

(vii) Stationary waves can be produced by the super-position of both the longitudinal and transverse waves.

(viii) Longitudinal stationary waves are formed in flutes and air columns.

(ix) Transverse stationary waves are formed in sono-meter, sitar, gitar and strings.

Graphical Representation of Stationary

Waves

Characteristics of Stationary Waves

(i) Some points of the medium are always stationary

i.e.,their amplitude is zero. These are called nodes.

(ii) In between the nodes there are points with maximum displacements. These are called antinodes.

(iii) The distance between two consecutive nodes or nearest antinodes is λ/2· The distance between a node and the nearest antinode is λ/4·

(iv) Excluding nodes every point of the medium exe-cutes simple harmonic motion about its mean position.

(v) The amplitudes of all the particles of the medium are not same. Amplitude at the nodes is zero and at antinodes maximum.

(vi) All the points occurring between two nodes vibrate in the same phase. They reach their respective positions of maximum displacement simultaneously and also pass through their mean position at the same time.

(vii) Like progressive waves the stationary wave do not proceed forward.

(viii) The variations of pressure and density are maxi-mum at nodes but are minimaxi-mum at antinodes.

Comparison of Progressive and Stationary Waves

Progressive Waves Stationary Waves

1. These waves move in medium with a definite speed.

1. These waves do not move in any direction and remain confined within two boun-daries.

2. All the medium particles in these waves vibrate with equal amplitude and time-period.

2. All the medium particles in these waves, except nodes, vibrates with equal time-periods but different amplitudes.

3. The phase of each particle changes continuously.

3. All the particles between two consecutive nodes are in same phase but the particles on the opposite sides of the node are in opposite phase.

4. None of the particles is permanently stationary. In the position of maximum displacement every parti-cle is momentarily statio-nary.

4. Node particles are perma-nently stationary; the rest are momentarily stationary in the position of maximum displacement.

5. The compressions and rarefactions move onward with a definite speed.

5. Compressions and rarefac-tions produce alternately at definite places.

6. Same changes of pressure and density occur at all points of medium.

6. Changes of pressure and density are maximum at nodes but minimum (zero) at antinodes.

7. These waves transmit every in the medium.

7. These waves do not trans-mit energy in the medium.

Reflection and Phase Changes in Mechanical

Waves

The behaviour of a wave at a boundary can be studied by sending pulses along a long narrow spring as shown in figure below :

Fixed end Heavy spring

Heavy spring Light spring Light spring (a) (b) (d) (c)

Light thread Spring 2

1

2 1

(i) In fig. (a), the left-hand end of the spring is fixed and a transverse upward pulse travelling towards it is reflected as a trough. A phase change of 180°°°° or ππππ rad

has occurred and there is a phase difference of half a

wavelength (λ/2) between the incident and reflected pulse.

(ii) In fig. (b), the left-hand end of the spring is atta-ched to a heavier spring and at the boundary the pulse is partly transmitted and partly reflected, the reflected

pulse being inverted.

(iii) In fig. (c), a pulse passes from a heavy spring on the left to a light spring. Partial reflection and transmission again occur but the reflected pulse is not turned upside

down.

(iv) In fig. (d), the left-hand of the long narrow spring is fastened to a length of a thin string and is in effect free. Here almost the whole of the incident pulse is reflected the right way up i.e., a crest is reflected as a crest and

no phase change occurs.

Phase Changes in Longitudinal Waves

(i) Phase changes also occur when longitudinal waves are reflected, as can be shown by sending pulses along a slinky spring to ‘denser’ and ‘less dense’ boun-daries, i.e., to fixed and free ends. At a fixed end a

compression is reflected as a compression, at a free it is reflected as a rarefaction.

(ii) Similar effects are obtained when sound waves are reflected in pipes with closed and open ends; a com-pression is reflected as a comcom-pression at a closed end and as a rarefaction at an open end.

Important Points

● When a transverse wave on a spring is reflected at a ‘denser’ medium, there is a phase change of 180_°. ● The phase change occurs in the case of the spring with

one end fixed for example, because there can be no displacement of the fixed end, it must be a node. The incident and reflected waves, therefore, cause equal and opposite displacements at the fixed end so that they superpose to give resultant zero displacement as shown in the figure below—

Incident wave Fixed end

Reflected wave

N N N N N

Vibrations of Air Columns

(i) An organ pipe is a pipe that sets in vibration the air enclosed in it when the air is blown into it. As a result sound is produced in it.

(ii) Organ pipes are of two types—closed end organ pipe and open end organ pipe.

(iii) A closed end organ pipe has one of its ends closed and the other open.

(iv) An open end organ pipe has both its ends open. (v) In a closed end pipe a node is always formed at the closed end and an antinode is formed at the open end.

(vi) Longitudinal stationary waves are formed in an organ pipe.

C.S.V.

November

2009

1078

(vii) Various stages of resonance in a closed end organ pipe are represented in the following diagrams :

A A A N 4 N N N N N t λ1 3λ2 4 5λ3 4

(viii) If the length of the pipe

l = λ1 4 then λ1 = 4l ∴ Frequency,n₁ = v λ1 = ₄v l

This frequency is called fundamental frequency or

fundamental note or first harmonic.

(ix) If l = 3λ2 4 then λ2 = 4l 3 ∴ Frequency, n₂ = v λ2 = 3₄v l = 3 n1

This frequency is called third harmonic or first

over-tone. (x) If l = 5λ3 4 then λ3 = 4l 5 ∴ Frequency, n₃ = v λ3 = 5₄v l = 5n1.

This frequency is called fifth harmonic or second

overtone.

(xi) Only odd harmonics can be produced in a closed end organ pipe. That is,

n1 : n2 : n3 ! …… : : 1 : 3 : 5 : ……

(xii) Longitudinal stationary waves are formed in an open end organ pipe too.

(xiii) The antinodes are formed at both the ends of an open pipe.

(xiv) Various stages of resonance in an open organ pipe have been represented in the following diagrams :

3λ3 λ2 λ1 2 2 A A A A A A A A N N N N N N A l (xv) If l = λ1 2 then λ1 = 2l ∴ Frequency, n1 = v λ1 = v 2l

This frequency is called the fundamental frequency or the fundamental note or the first harmonic.

(xvi) If l = λ2 then n2 =

v

λ2

= v

l = 2n1.

This frequency is called the second harmonic or

first overtone. (xvii) If l = 3λ3 2 then λ3 = 2l 3 ∴ n3 = v λ3 = 3v 2l = 3n1

This frequency is called the third harmonic or

second overtone.

(xviii) Both the odd and even harmonics are produced in an open end organ pipe. That is,

n1 : n2 : n3 : …… : : 1 : 2 : 3 : ……

(xix) The sound emitted by an open end organ pipe is musical.

End Correction

(i) In an organ pipe antinode is formed a bit above the open end as shown below by distance e.

e e e A 4 A N N A l λ l 2 λ

(ii) The length of the vibrating air column is a little greater than the length of the pipe.

(iii) The distance from the free end of the pipe to the antinode is called the end-correction represented by e.

(iv) Length of air column in closed end pipe = l + e.

Length of air column in open end pipe = l + 2e. (v) If r be the radius of pipe then the end-correction

e = 0·6r.

(vi) Frequency of the fundamental note of closed end pipe

n₁ = ₄₍ v

l + 0·6r)

and the frequency of the fundamental note of the open end pipe

n2 =

v

2(l + 1·2r) ·

(vii) The frequency of the fundamental note of open end pipe is not exactly the double of that of the closed end pipe but is a bit less.

Resonance Tube

(i) Resonance tube is a closed organ pipe with an air column of variable length.

C.S.V.

November

2009

1079

(ii) By resonance tube we can determine the speed of sound in air and the frequency of tuning fork.

(iii) When the frequency of the air column of reso-nance tube becomes equal to that of the tuning fork, resonance occurs and the amplitude of vibrations of air column becomes very large. A loud sound is heard in such a case. A N N N A 4 4 λ 3λ l l₂

(iv) If the lengths of air column at first and second resonance be l₁ and l₂ respectively, then

l₁ + e = λ₄

and l₂ + e = 3λ₄

∴ λ = 2(l2 – l1)

Speed of sound, v = 2n(l₂ – l₁) and end-correction, e = l2 – 3₂ l1

(v) Speed of sound at 0°C is given by v0 = vt – 0·61t

where v_t is the speed of sound at t°C.

Vibrations of Stretched String

(ii) On both the ends of string there are nodes, and an antinode is there in the middle.

(iii) The speed of transverse wave in a stretched string is given by

v = T

m

where T and m are respectively the tension and mass per unit length of the string.

(iv) Modes of vibration in a stretched string are as under : l A N N N N N N N N N A A A A A 2 2 2 2 2 2 2 2 λ λ λ λ λ λ λ1 = λ2 3λ3

(v) If a string of length l vibrates in one loops then λ1 = 2l and frequency n₁ = ₂v l = 1 2l T m ·

This frequency is called the fundamental note or

first harmonic.

(vi) If the string vibrates in two loops, then

λ = l and n₂ = v_l = 2n₁.

This frequency is called the first overtone or second

harmonic.

(vii) If the string vibrates in three loops, then 3λ3 2 = l ⇒ λ3 = 2l 3 ∴ n3 = 3v 2l = 3n1.

This frequency is called the second overtone or

third harmonic.

(viii) Both the odd and even harmonics are emitted from a stretched string. That is,

n₁ : n₂ : n₃ : …… : : 1 : 2 : 3 : ……

Laws of Transverse Vibrations in a Stretched

String

(i) Law of length : n ∝ 1_l ; if T and m are constant.

(ii) Law of tension : n ∝ T ; if l and m are constant. (iii) Law of mass : n ∝ 1_m ; if T and l are constant. (iv) Law of radius : n ∝ 1_r ; if T, l and the density d

of the string are constant; r being the radius of string.

(v) Law of density : n ∝ 1

d ; if T, l and r are

con-stant.

Melde’s Experiment

(i) Melde’s experiment is a simple and beautiful example for the demonstration of stationary waves and the harmonics of their transverse vibrations.

(ii) Melde’s experiment is performed by two methods. (iii) Transverse arrangement of vibrations : (a) In this arrangement the tuning fork is held such

that the direction of its vibration is perpendicular to the direction of length of string.

(b) In this arrangement the frequencies of the tuning fork and the string are equal.

(c) If the tension T in the string is adjusted such that

p loops areproducedin the string of length l, then

p2T = 4n2l2m = Constant,

where m is the mass per unit length of the string. This is Melde’s law.

(iv) Longitudinal arrangement of vibrations : (a) In this arrangement the tuning fork is held such

that the direction of its vibration is along the length of the string.

(b) In this arrangement p2T = n2l2m = Constants.

(c) Here the frequency of string is half the frequency of tuning fork.

SOME IMPORTANT SOLVED EXAMPLES

Example 1. An open end organ pipe emits a note of frequency 256 Hz which its fundamental. What would be the smallest frequency produced by a closed end pipe of the same length ?

Solution :

Example 2. An air column with a tuning fork of frequency 256 Hz gives resonance at column lengths 33·4 cm and 101·8 cm. Deduce (i) the end correction, and (ii) the speed of sound in air.

Solution :

Example 3. A pipe 30 cm long is open at both ends. Which harmonic mode of the pipe is resonantly excited by a 1·1 kHz source ?

(Given speed of sound = 330 ms–1)

Solution :

Example 4. A wire is under tension of 32N and length between the two bridges is 1 m. A 10 m length of the sample of the wire has mass of 2g. Deduce the speed of transverse waves on the wire and frequency of the fundamental.

Solution :

Example 5. The length of the sonometer wire bet-ween two fixed ends is 100 cm. Where should the two bridges be placed to divide the wire into three seg-ments whose frequencies are in the ratio of 1 : 2 : 3 ?

Solution :

Example 6. A tuning fork and an air column at

51°°°°C produce 4 beats in one second when sounded

together.Thesametuningproduces 1 beat per second

when the temperature of the air column is reduced to 16°°°°C. Determine the frequency of the tuning fork.

OBJECTIVE QUESTIONS

at both ends is 0·5 m. Calculate the fundamental frequency of the pipe if the speed of sound in air is 350 m/s. If one end of the pipe is closed, then what will be its fundamental frequency ? (A) 175 Hz, 350 Hz (B) 300 Hz, 150 Hz (C) 350 Hz, 175 Hz (D) 150 Hz, 350 Hz

2. A resonance tube is resonated with a tuning fork of frequency 512 s–1. Two successive lengths of the resonated air-column are 16·0 cm and 51·0 cm. The experiment is performed at room temperature 40°C. Calculate the speed of sound and end-correc-tion at 0°C—

(A) 334 ms–1, 1·5 cm (B) 334 ms–1, 2·1 cm (C) 350 ms–1, 1·5 cm (D) 350 ms–1, 2·1 cm

3. A wire of length 1·5 m under tension emits a fundamental note of frequency 120 Hz. (a) What would be its fundamental fre-quency if the length is increased by half its length under the same tension (b) By how much should the length be shortened so that the frequency is increased three-fold ?

(A) 90 Hz, 1·0 m (B) 80 Hz, 1·0 m (C) 80 Hz, 0·5 m (D) 100 Hz, 0·5 m

4. A string A has thrice the length, thrice the diameter, thrice the tension and thrice the density of anotherwireB. Whichovertoneof A will have the same frequency as the fundamental of B ?

(A) 9th (B) 8th

(C) 6th (D) 10th

5. A steel rod 100 cm long is clamped at its middle. The funda-mental frequency of longitudinal vibrations of the rod is given to be 2·53 kHz. What is the speed of sound in steel ?

(A) 2·53 km/s (B) 253 km/s (C) 5·06 km/s (D) None of these

6. A pipe 20 cm long is closed at one end. Which harmonic mode of the pipe is resonantly excited by a 425 Hz source ? Will this same source be in resonance with the pipe if both ends are open ?

(Speed of sound = 340 ms–1) (A) First harmonic, No

(B) Second harmonic, No (C) Third harmonic, No (D) None of these

7. Thepitch of the fundamental tone of anopen organ pipe 66 cm long is the same as that of a stretched string 20 cm long vibrating trans-versely. If the mass per unit of

the string is 0·01 kg/m. Find the tension in the string in kg-wt— (Speed of sound in air = 330 ms–1) (A) 100 kg-wt (B) 102 kg-wt (C) 15·0 kg-wt (D) 10·2 kg-wt 8. Two perfectly identical wires are

in unison. When the tension in one wireisincreased by 1%, then onsoundingtogether, 3 beats are heard in 2 second. What is the frequency of each wire ?

(A) 350 Hz (B) 256 Hz

(C) 300 Hz (D) None of these

9. Two tuning forks A and B when sounded together give 4 beats/s. A is unison with the note emitted by a 0·96 m length of a sono-meter wire under a certain tension. B is in unison with 0·97 m length of the same wire under the same tension. Calculate the frequency of the fork—

(A) 388 Hz (B) 512 Hz

(C) 256 Hz (D) 540 Hz

10. Two tuning forks A and B when sounded together give 8 beats/ sec. Fork A resonates with a closed column of air 16 cm long and B with an open column 32·5 cm long. Calculate their frequen-cies—

(A) 520 Hz, 512 Hz (B) 512 Hz, 504 Hz (C) 256 Hz, 248 Hz (D) None of these

ANSWERS WITH HINTS