NTSE Interview Question_SAT

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Subject : Mathematics DPP No. __ Class : VIII

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. If ax_{= b, b}y_{= c and c}z_{= a, then find the value of}

xyz. Sol. If ax_{= b, b}y_{= c, c}z_{= a,}  ax = b  (cz)x = b  czx = b  (by)zx = b  bxyz = b  xyz = 1.

2. In the adjoining figure, If PQ is the diameter of the circle, then find SQP.

150º S

Q P

R

Sol. Construction - Join PS

PSQ = 90º

[Angle in a semi circle is a right angle] As PQRS is a cyclic quadrilateral P + R = 180º P = 180º – 150º = 30º In PSQ SPQ + SQP + PSQ = 180º SQP = 180º – (90º + 30º) = 180º – 120º = 60º.

3. In figure, ABCD is a rectangle having AB = 20 cm and BC = 14 cm. Two sectors of 180º have

been cut off. Calculate, the area of shaded re-gion.

D C

A B

Sol. Area of shaded region = Area of rectangle –

Area of 2 semi circle

= (14 × 20) – 2 _       2 ) 7 ( 2 = 280 – 49 × 7 22 = 280 – 154 = 126 cm2 01

4. A started a business by investing Rs. 8000. After x months B joined the business invested Rs. 12,000. If the profit earned is equal by both at the end of the year, then find the value of x.

Sol. Let B’s money Invested for (12 – x) months.

8000 × 12 : (12 – x) × 12000 = 1 : 1



(12 – x) × 12000 = 12 × 8000



(12 – x) = 12000 8000 12 = 8 months  12 – x = 8



x = 4 months.

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Subject : Mathematics DPP No. __ 02 Class : VIII

1. In Given figure, find

_

C,

_

D and

_

DBC.

Sol. AD = AB

D = ABD

2(D) = 100º ABD = 50º = D

And

ABC = C [As AB = AC]

2(ABC) = 80º ABC = C = 40º DBC = 50 + 40 = 90º



C = 40º,



D = 50º ,



DBC = 90º.

2. A sphere of radius 3 cms is dropped into a cylindrical vessel of radius 4 cms. If the sphere is submerged completely, then find the height (in cm) to which the water rises.

Sol. Volume of sphere = 3 4

× × 3 × 3 × 3 = 36 

Area of bottom of a cylinder = × 4 × 4

let h be height to which water raise. Then, volume of water raise

= × 4 × 4 × h = 16  h

Now, according to the problem 16  h = 36 

h = 4 9

= 2.25 cm.

3. Find the value of expression

225 154 108 25 10    . Sol. ₁₀_ ₂₅_ ₁₀₈_ ₁₅₄_ ₂₂₅ = ₁₀_ ₂₅_ ₁₀₈_ ₁₅₄_₁₅ = ₁₀_ ₂₅_ ₁₀₈_ ₁₆₉ = ₁₀_ ₂₅_ ₁₀₈_₁₃ = ₁₀_ ₂₅_ ₁₂₁ = 10 2511 = ₁₀_ ₃₆ = ₁₀_₆ = ₁₆ = 4.

4. There are four prime numbers written in ascending order. The product of the first three is 385 and that of the last three is 1001. Find the last number.

Sol. Let the given prime numbers be a, b, c, d. Then, abc = 385 and bcd = 1001.  1001 385 bcd abc  _ 13 5 d a  . So, a = 5, d = 13.

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N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

03

1. How many balls, each of radius 1 cm, can be made from a solid sphere of lead of radius 8 cm ?

Sol. Volume of the spherical ball of radius 8 cm = _

3 4

× 83 cm3

Also, volume of each smaller spherical ball of

radius 1 cm = _ 3 4

× 13 cm3.

Let n be the number of smaller balls that can

be made. Then, the volume of the larger ball is equal to the sum of all the volumes of n smaller balls. Hence, _ 3 4 × n =  3 4 × 83  n = 83 = 512.

2. In the given figure O is the centre of the circle. The angle subtended by the arc BCD at the centre is 1400_{BC is produced to P. Find}

BAD

and DCB.

Sol. In the given figure,

BAD = 2 1 BOD BAD = 2 140 = 70º

ABCD is a cyclic quadrilateral A + C = 180º

C = 180º – 70º = 110º BCD = 110º

3. Find the remainder when p(x) = 4x3

– 12x2 +

14x – 3 is divided by g(x) = x –

2 1 .

Sol. By remainder theorem, we know that p(x) when divided by g(x) =        2 1 x _{gives a remainder} equal to p       2 1 . Now, p(x) = 4x3 – 12x2 + 14x – 3  p       2 1 = 4 3 2 1       – 12 2 2 1       + 14       2 1 – 3 = 8 4 – 4 12 + 2 14 – 3 = 2 1 –3 + 7 – 3 = 2 3

Hence, required remainder = p       2 1 = 2 3

4. The milk and water in two vessels A and B are in the ratio 4 : 3 and 2 : 3 respectively. In what ratio, the liquids in both the vessels be mixed to obtain a new mixture in vessel C containing half milk and half water ?

Sol. Let the C.P. of milk be Rs. 1 per litre. Milk in 1 litre mixture of A =

7 4_{litre ;}

Milk in 1 litre mixture of B = 5 2

litre;

Milk in 1 litre mixture of C = 2 1 litre.  C.P. of 1 litre mixture in A = Rs. 7 4 ; C.P. of 1 litre mixture in B = Rs. 5 2 . Mean price = Rs. 2 1

By the rule of alligation, we have :

 Required ratio = 10 1 : 14 1 = 7 : 5.

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Subject : Mathematics DPP No. __ 04 Class : VIII 1. The sum of two angles of a triangle is half of a

right angle and their difference is 1º more than

5 2

th of a right angle, then find smallest angle of the triangle.

Sol. Let the two angles be x & y Given x + y = 2 1 (90º) = 45º ...(i) x – y = 5 2 (90º) + 1 = 37 ...(ii)

Adding (i) & (ii) 2x = 82º

x = 41º

y = 4º

Smallest angle = 4º.

2. A rhombus whose area is 225 sq. cm has one of its diagonal twice as long as the other. Find the length of the longer diagonal.

(A) 15 cm (B) 45 cm (C*) 30 cm (D) 60 cm

Sol. Area of Rhombus = 2 1 × d1d2 Given : A = 225 sq. cm d₁ = 2d₂ 225 = 2 1 × 2d2× d2 225 = d₂2 d₂ = ₂₂₅ d₂ = 15 cm

So, longer diagonal = 2 × 15 = 30 cm.

3. The average age of 7 members of a family is 18 years. If the head of the family is excluded the average age of the rest of the members would be 5 years less. Find the age of the head of the family.

Sol. Average age of 7 members = 18 yrs.

 Total age of the 7 members

= 18 × 7 = 126 yrs.

When the head is excluded the average age = 18 – 5 = 13 yrs.

Total age of the 6 members = 13 × 6 = 78 yrs.

Age of the head of the family

= 126 – 78 = 48 yrs.

4. Find the value of b.

Sol. 2a = AOC a =

2 100º

= 50º a = 50º

ABCD is a cyclic quadrilateral

B + D = 180º b + a = 180º

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N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

05

1. Find the maximum length of a pencil that can be kept in a rectangular box of dimensions 8 cms ×

6 cms × 2 cms.

Sol.  = 8 cm

b = 6 cm h = 2 cm

Maximum length of pencil = Length of diagonal = 2 2 2 h b    = 886622 = 64364 = 104 cm.

2. The diameter of the wheel of a bus is 140 cm. How many revolutions per minute must the wheel make in order to keep a speed of 66 km per hour ?

Sol. Distance covered in 1 minute =

        60 100 1000 66 cm

Distance covered in 1 revolution

= circumference of wheel =         70 7 22 2 _{cm =} 440 cm.  Number of revolutions =       440 110000 = 250.

3. Two regular polygons are such that the ratio between their number of sides is 1 : 2 and the ratio of the measures of their interior angles is 4 : 5. Find the number of sides of each poly-gon. Sol. n 2 180 ) 2 n 2 ( n ) 180 )( 2 n (   = 5 4 ) 1 n ( 2 ) 2 n ( 2   = 5 4 4n – 4 = 5n – 10 n = 6 2n = 12 n = 6

So, number of sides of polygons are 6 and 12.

4. In the given figure, ABC is an equilateral

triangle the length of whose side is equal to 10 cm, and DBC is right-angled at D and BD = 8

cm. Find the area of the shaded region.

Sol. Ar. of ABC =

4 3 a2 = 100 4 3 = ₂₅ ₃ cm2 (BC)2 = (BD)2 + (DC)2 (10)2 = (8)2 + (DC)2 DC = 6 cm Area BDC = 2 1 × 8 × 6 = 24 cm2 Shaded region = 25 3 – 24 cm2

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Subject : Mathematics DPP No. __ 06 Class : VIII 1. Find the 8th number if the average of 15

numbers is 18, the average of first 8 is 19 and that last 8 is 17. Sol. Average = numbers of . No numbers of Sum 18 = 15 numbers of Sum Sum of numbers = 18 × 15 = 270

Average of first 8 numbers =

8 numbers 8 first of Sum

sum of first 8 nos.= 19 × 8 = 152

Average of last 8 nos. =

8 . nos 8 last of sum

Sum of last 8 nos. = 17 × 8 = 136

Eight number

= Sum of first 8 nos. + sum of last 8 nos. –

sum of 15 nos.

= 152 + 136 – 270 = 288 – 270 = 18.

2. If x : y = 3 : 4, find (4x + 5y) : (4x – 5y).

Sol. _yx = 4 3  y 5 x 4 y 5 x 4   = 5 y x 4 5 y x 4                   =                 5 4 3 4 5 4 3 4 =



3 5



) 5 3 (   = 2 8  = – 4.

3. Consider the rectangle ABCD as shown, E is a point on CD such that AE = 3, BE = 4 and AE  BE. Then find the area of rectangle

ABCD. A D _C B 3 4 E Sol. A D _C B 3 4 E F In AEB AB2_{= 3}2_{+ 4}2_{= 5}2  AB = 5 Area of AEB = 2 1 × 5 × EF = 2 1 × 3 × 4 = = 2 1 × 5 × EF EF = 5 12 Now, AD = EF = 5 12

Area of rectangle ABCD = 5 ×

5 12

= 12 sq. unit.

4. There is a cylinder circumscribing the hemisphere such that their bases are common. Find the ra-tio of their volume.

Sol. Let radius of cylinder = radius of hemisphere = r So, height of hemisphere = r

Volume of hemisphere = 3 2 r3 Volume of cylinder = r2× r  _Volume_of_cylinder hemisphere of Volume = ₃ 3 r r 3 / 2   = 3 2 .

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N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

07

1. Find the third proportional to 16 and 36.

Sol. Let the third proportional to 16 and 36 is x. Then, 16 : 36 : : 36 : x  16 × x = 36 × 36  x = 16 36 36 = 81.

 Third proportional to 16 and 36 is 81.

2. Twelve years hence, a man will be four times as he was twelve years ago, then find his present age.

Sol. Let his present age be x. According to problem x + 12 = 4 (x – 12)

– 3x = – 48 – 12

3x = 60 x = 20 years .

3. If pqr = 1, then find the value of the expression

                1 1 1 r p1 1 r q 1 1 q p 1 1 . Sol. _               1 1 1 r p1 1 r q 1 1 q p 1 1 =                p rp 1 p 1 qr r r 1 pq q q = _               pq q 1 pq pq q 1 1 1 pq q q        pq 1 r  = _           1 pq q 1 pq q = 1.

4. Find the number of diagonals that can be drawn in a regular heptagon.

Sol. Number of diagonals =





2 3 n n  =





2 3 7 7  = 14.

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Subject : Mathematics DPP No. __ 08 Class : VIII 1. A sum of money invested at simple interest

amounts to Rs.800 in 3 years and to Rs.840 in 4 years. Find the rate of interest per annum.

Sol. (A)₃ = Rs. 800 (A)₄ = Rs. 840

So, (S.I.)_R for last year = 840 – 800 = Rs.40

S.I. = 100 PRT 40 = 100 1 R 800  R = 800 100 40 R = 5%.

2. P is a prime number greater than 5. What is the remainder when P is divided by 6?

Sol. Any prime nu mber greater than 3 is of the form 6k ± 1.

So, the remainder is 1or 5.

3. A right circular cone of diameter k cm and height 12 cm rests on the base of a right circular cylinder of radius k cm (their bases lie in the same plane, as shown). The cylinder is filled with water to a height of 12 cm. If the cone is then removed, the height to which the water will fall, is

(A) 1 cm (B) 2 cm (C) 3 cm (D) 4 cm Sol. - - - - - - - - - _{- - -} - - - - - - - - - - - - - - -

Volume of water in the cylinder = Volume of

cylinder to a height 12 cm – Vol. of cone of

height 12 cm. = k2 12 – 2 2 k 3 1        _{× 12} = 12k2– k2 = 11k2

Volume of cylinder when cone was immersed in it = k212.

So, water will fall by height = (12 – 11) = 1

cm.

4. A 400 m long train is running at the speed of 60 km per hour. Then find the time in which It crosses a bridge of length 800 m.

Sol. Speed of train = 60 kmph

= 60 × 18 5 = 3 50 m/s Time taken = train of speed bridge of length train of length  = 3 / 50 800 400 = 50 3 1200 = 72 sec.

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N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

09

1. If the exterior angle of a regular polygon is 3 1

rd of its interior angle, then find the number of sides of the polygon.

Sol. Let an exterior angle of the given polygon is x then interior angle = (180 – x)

According to question x = 3 1 (180 – x)  3x = 180 – x  4x = 180  x = 0 0 45 4 180 

 Each exterior angle = 450  No of sides = ₄₅

360 = 8.

2. Find the value of

ab b a ca a c bc c b x x x x x x 1 1 1 . .                         . Sol. ab 1 b a ca 1 a c bc 1 c b x x . x x . x x                         =

_{ }

ab b a ca a c . bc c b ) x ( x x    =

_{ }

_x abcb_abccacab

 

abc bc – ac ab – bc ac ab x   

 

abc 0 x =

 

x = 1.0

3. By melting a solid cylindrical metal, a few conical materials are to be made. If three times the radius of the cone is equal to twice the radius of the cylinder and the ratio of the height of the cylinder and the height of the cone is 4 : 3, find the number of cones which can be made.

Sol. Let R be the radius and H be the height of the cylinder and let r and h be the radius and height of the cone respectively. Then,

3r = 2R And H : h = 4 : 3 ....(i)  3 4 h H   3H = 4h ....(ii)

Let n be the required number of cones which can be made from the materials of the cylinder. Then, the volume of the cylinder will be equal to the sum of the volumes of n cones. Hence, we have R2H = 3 n r2h  3R2H = nr2h  n = h r 3 4h 4 9r 3 h r H 3R 2 2 2 2   

[_From (i) and (ii), R = 2 r 3 and H = 3 h 4 ] = 4 3 4 9 3    = 9

Hence, the required number of cones is 9.

4. What least value must be assigned to _* so that number 63576_*2 is divisible by 8 ?

Sol. If we put 3 or 7 instead of * then number

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Subject : Mathematics DPP No. __ 10 Class : VIII 1. If 2x_{= 8}y + 1_{and 9}y_{= 3}x – 9_{, then find the value of}

x + y. Sol. 2x_{= 8}y + 1 2x_{= (2)}3y + 3 x = 3y + 3 ....(i) and 9y_{= 3}x – 9 32y_{= 3}x – 9 2y = x – 9 x = 2y + 9 ....(ii) From (i) & (ii)

3y + 3 = 2y + 9 y = 6.

So, x = 3(6) + 3 = 21.

 x + y = 6 + 21 = 27.

2. In triangle ABC, AD BC and point D divides

BC in the ratio 2 : 5, then find ar(ABD) :

ar(ACD). Sol. Let BD = 2x, DC = 5x A B C D Area of ABD = 2 1 × BD × AD = 2 1 × 2x × AD Area of ADC = 2 1 × DC × AD = 2 1 × 5x × AD  _Area_of _ADC ABD of Area   = AD x 5 2 1 AD x 2 2 1     = 5 2

3. The numerator and denominator of a fraction are in ratio 2 : 3 . If 6 is subtracted from the numerator, the result will be

3 2

of the original fraction. What is the value of the numerator ?

Sol. Let the fraction in k 3

k 2

if 6 is subtracted from numerator

k 3 6 – k 2 =       k 3 k 2 3 2 k 3 6 – k 2 = 9 4 k = 9  Numbers = 2k = 2 × 9 = 18. 4. If q p = 2 3 2       ÷ 0 7 6      

find the value of

2 p q         Sol. q p = 2 3 2       ÷ 0 7 6       q p = 2 3 2       ÷ 1 q p = 2 3 2       q p = 9 4 2 2 q p = 81 16  2 2 p q = 16 81 .

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N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

11

1. The LCM of two number is 12 times their H.C.F. The sum of their H.C.F. and L.C.M. is 403. If one of the numbers is 93, then find the other number. Sol. LCM = 12(H.C.F.) LCM + H.C.F. = 403 12(H.C.F.) + H.C.F. = 403 13(H.C.F.) = 403 H.C.F. = 13 403 = 31 So, LCM = 12 (H.C.F.) = 12 × 31 = 372

Also, LCM × HCF = Product of two number

373 × 31 = 93 × x x = 93 31 372 x = 124.

2. Find the mean of the factors of 10.

Sol. Factors of 10 are 1, 2, 5 & 10. 5 . 4 4 18 4 10 5 2 1 x      

3. Find the value of a.

Sol. ROS = 2RQS RQS = 2 42 = 21º RQS = 21º

PRQ = 90º [Angle in a semi -circle is a right

angle] PRQ + QRT = 180º [L.P.] QRT = 180º – 90º = 90º In QRT QRT + RQT + a = 180º a = 180º – [90º + 21º] = 180º – 111º = 69 a = 69º.

4. In the figure, parallel to m and AX and AY are transversals. Then, find the value of the angle (x + y – z).

Sol.

 || m, z = 70º, x = 50º & y = 60º

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Subject : Mathematics DPP No. __ 12 Class : VIII

1. P is a point inside ABC. If PBA = 20º, BAC = 50º and, PCA = 35º, then find the

measure of BPC. Sol. In APB, APB = 180º – a – 20º In APC, APC = 180º – b – 35º APB + APC = 360º – (a + b) – 55º = 360º – 50º – 55º = 360º – 105º = 255º Required BPC = 360º – 255º = 105º.

2. Find the value of a, b,c & d.

Sol. d = 95º

[The exterior angle formed by producing one side of the quadritral is equal interior opposite angle of quadrilateral ]

a = 80º

As ABED is a cyclic quadrilateral

a + b = 180º , c + 95º = 180º b = 180º – 80º , c = 180º – 95º b = 100º , c = 85º

3. If ( a b) = 17 and ( ab) = 72 then, find the value of ( a b). Sol. ₍ _a _b₎2  = ( a b)2 – 4 a × b  ( a – b)2 = (17)2– 4 × 72  ( a – b)2 = 289 – 288  ( a – b )2_{= 1}  a – b = 1 Hence, ( a b) = 1  ( a b) = 1  ( a b) = 1

4. For what values of a is 2x3_{+ 11x + a + 3}

exactly divisible by (2x – 1) ?

Sol. Let p(x) = 2x3_{+ ax}2_{+ 11x + a + 3 be the given}

polynomial. If p(x) is exactly divisible 2x – 1,

then (2x – 1) is a factor of p(x).  p       2 1 = 0 _          2 1 x 0 1 x 2   2 × 3 2 1       + a × 2 2 1       + 11 × 2 1 + a + 3 = 0  4 1 + 4 a + 2 11 + a + 3 = 0  4 12 a 4 22 a 1    = 0  4 35 a 5  = 0  5a + 35 = 0  a = – 7

Thus, the given polynomial is divisible by 2x – 1, if a = – 7.

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Subject : Physics DPP No. __ Class : VIII

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

01

1. Which mirror is used in cars to see the traffic coming from behind and why ?

Ans. Covex mirror, because it forms diminished image and covers wide area.

2. Name the component of sunlight that mainly carries heat with it.

Ans. Infra red radiation.

3. A runner running along a circle, runs the circle completely. What is his displacement ?

Ans. Initial and final positions are same so displacement will be zero.

4. At what temperature, Fahrenheit and degree celsius scale measure same temperature :

Ans. – 40ºC = – – 40º F

Sol. Relation between Celsius and Fahrenheit scale

9 32 F 5 C   ,

Let, the same temperature is x

9 32 x 5 x   On solving, we get, x = – 40º 5. When a body is stationary ?

Ans. The combination of forces acting on it balance each other

(14)

Subject : Physics DPP No. __ 02 Class : VIII

1. Name the lens, which can produce real as well as virtual image.

Ans. Convex lens.

2. Which cell converts sunlight into current ?

Ans. Solar cell

3. The value of 5ºC in ºF and K scale will be respectively :

Ans. 41ºF, 278 K

Sol. Relation between Celsius and Fahrenheit scale

9 32 F 5 C  

So corresponding value of 5ºC in Fahrenheit scale is

9 32 F 5 5   F = 41ºF

Relation between Celsius and Kelvin scale T(K) = T(ºC) + 273 = 5 + 273 = 278 K

4. Are all sounds audible to us ? What is the audible range of frequencies for human beings ?

Ans. No, audible range is 20 Hz to 20 KHz

5. The direction of the magnetic field at a point P above the wire carrying current wire as shown in figure is :

P Current Ans. out of the page (By right hand thumb rule)

(15)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. In what form of waves, sound travel in air ?

Ans. Longutidunal Waves

2. Which is the hottest planet of solar system ?

Ans. Venus

3. Which process is used for refining of petroleum ?

Ans. Fractional distillation

4. A temperature difference of 30ºC in the Fahrenheit scale is

Ans. 54ºF

Sol. Relation between ºC and ºF scale

9 32 F 5 0 C    9 F 5 C    = 30ºC F = 5 9 × C = 5 9 × 30 F = 54ºF

5. A porter is moving on a platform with a box of 10 kg on his head. In moving 20 m, what weill be the work done by the force of gravity ? (g = 10 m/s2) :

Ans. Zero

Sol. In the question displacement and force of gravity are perpendicular to each other, so work done by force of gravity will be zero.

(16)

Subject : Physics DPP No. __ Class : VIII

1. Give the S.I. unit of that physical quantity on which loudness or softness of sound depends ?

Ans. Metre ( loudness or softness of sound depends on amplitude of sound waves)

2. Out of water and ice : which has higher density ?

Ans. Water has higher density than ice.

3. Which is the nearest star from earth apart from sun ?

Ans. Alpha Centuari

4. A boy is suffering from fever and doctor said that his body temperature is 105. Then temperature should be expressed in :

Ans. ºF

5. Write the name of rays parallel and close to the principal axis.

Ans. Paraxial rays

(17)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. Give the S.I. unit of that physical quantity on which pitch of a sound depends.

Ans. Hertz (Pitch of sound depends on frequency of sound)

2. How many Newton are there in 1 kilogram weight ?

Ans. 9.8 N (F = mg = 1 × 9.8 = 9.8N)

3. Which instrument is used to measure atmospheric pressure ?

Ans. Barometer

4. The sun is at the centre of :

Ans. Solar system

5. 1 electron volt is equal to :

Ans. 1.6 × 10–19_joule

Sol. If electron is accelerated by 1 volt, then its energy will be 1 e.v. E= qv = 1.6 × 10–19

× 1 = 1.6 × 10–19_joule

(18)

1. At what temperature does kelvin and Fahrenheit gives the same reading ?

Ans. 574.25 ºF = 574.25 K

Sol. Relation between kelvin and Fahrenheit scale

5 273 K 9 32 F    (_ F = K = x) 5 273 x 9 32 x    9x – 2457 = 5x – 160 x = 574.25

2. Which nuclear reaction takes place in nuclear reactor ?

Ans. Nuclear fission reaction

3. In which direction the buoyant force acts on an object ?

Ans. Vertically upward

4. When a body is projected into space in gravitational field of earth, there is an increase in its :

Ans. Potential energy (Potential energy will increase, Kinetic energy will decrease and M. energy will remain same)

5. Write the name of two renewable sources of energy ?

Ans. Wood and Soil

(19)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. What is the shape of “Milky Way” galaxy.

Ans. Spiral

2. Solar cells are made of :

Ans. semiconductors

3. Water falls from a height of 100 m. Find the change in temperature of water at the bottom.

Ans. 0.24 ºC

Sol. Let m kg water be falling from height of 100m. So, potential energy of water at height h, U = mgh, g = 10 m/s2_{, h = 100 m}

When water reach at bottom then potential energy will convert into kinetic energy.  K.E. = mgh

This K.E. will increase the temperature of water on converting into heat energy: i.e. Q = msT = K.E. or msT = mgh Change in temperature, T = 4200 100 10 s gh   = 0.24 ºC

4. The time interval between seeing the lightning and the thunder is 5 seconds. Calculate the approximate distance of the clouds.

Ans. 1660 m

Sol. We know that,

Distance = Velocity × time

Here, Velocity (of sound) = 332 ms–1 Time = 5s

Distance of the clouds = 332 × 5 = 1660 m 5. Write the numerical ratio of displacement to distance .

Ans. equal to or less than one (Displacement _Distance)

(20)

1. The frequency of a wave travelling at a speed of 100m/s is 50 Hz. Its time period is :

Ans. 0.02s

Sol. Given : Frequency = 50 Hz We know, Time period =

frequency 1 = 50 1 = 0.02s

2. With the rise of temperature, the velocity of sound will increase or decrease.

Ans. Increase (_ v_t = v₀ + 0.61t)

3. Specific heat of water at 0ºC(in Cal/gºC) is :

Ans. 1 (1 cal/g × ºc)

4. Write the relation between frequency (N) and time period (T).

Ans. N = T 1

5. Name the device used to measure the distance in vehicles.

Ans. Odometer

(21)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. Which mirror is used as a rear view mirror in vehicle ?

Ans. Convex mirror (It covers wide area, image will always be diminished, virtual and between pole and focus point)

2. Give the main constituent of natural gas.

Ans. Methane

3. 420 Joule of energy supplied to 10g of water. Find raise in its temperature. [Specific heat of water = 4.2J/gºC]

Ans. 10ºC Sol. Q = msT here Q = 420 J, m = 10 g, s = 4.2 J/gºC T = 2 . 4 10 420  = 10ºC

4. The distance between two consecutive compressions is 1.4 m. Find the wavelength of the wave.

Ans. Wavelength = Distance between two consecutive compressions = 1.4 m 5. How many joule are there in 1 calorie ?

Ans. 4.2 J (1 cal = 4.2 J )

(22)

1. What is the S.I. unit of temperature ?

Ans. Kelvin

2. Which lens is used as Magnifying glass ?

Ans. Convex lens

3. The first thermometer was developed by :

Ans. Galileo

4. How much heat would be required to convert 14 kg of ice at 0ºC into water ?

Ans. 4704 KJ

Sol. Given : m = 14 kg, L = 80 cal/gram = 80 Kcal/kg

In this process heat required is equal to heat of fusion of ice: Q = mL

= 14 × 80 × 4200 = 4704 KJ

5. A wire of _length is placed in a magnetic field B, If the current in the wire is I. Find the maximum magnetic force on the wire.

Ans. F = B_{ }

(23)

Subject : Chemistry DPP No. __ Class : VIII

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. When an atom is converted into an anion, then what will be the ratio between electron and proton ?

Sol. _p

e–

> 1

2. What is brine ?

Sol. 30% sodium chloride solution is called brine.

3. Complete the equation ? Na₂O + 2HCl A + B

Sol. A = 2NaCl, B = H₂O

4. In foam type fire extinguisher which substance is added to produce foam ?

Sol. Saponin

5. Why does carbon form a large no. of compounds ?

Sol. Due to catenation Catenation

01

(24)

1. Name the allotropic form of carbon which has lustre ?

Sol. Graphite

2. How is m.p. of ice affected on adding salt to it ?

Sol. Melting point decreases

3. Which gas is formed by the reaction between nitrogen and oxygen during lightning ?

Sol. NO (Nitric oxide)

4. What is the composition of bronze ?

Sol. Bronze is an alloy of 90% copper and 10% tin.

5. What is biochemical oxygen demand ?

Sol. Measurement of rate of oxygen utilisation by a unit volume of water over a period of time.

(25)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. What is the structure of methane (CH₄) molecule ?

Sol. Tetrahedral

2. Fe O (s) + 3CO(g) 2 3 3CO (g) + 2Fe(s)₂

Which reactant is reducing agent in the given reaction ?

Sol. CO

3. Which acid present in the atmosphere of venus ?

Sol. Oil of vitriol (H₂SO₄)

4. Which oxide of nitrogen is called 'Laughing gas'?

Sol. Nitrous oxide (N₂O)

5. How many electrons can be occupied in M shell

-Sol. 18

(26)

1. What is the formula of dry ice ?

Sol. CO₂(s)

2. Name the gas which plays the major role in the global warming ?

Sol. CO₂

3. Give the formula of " aqua fortis"

Sol. HNO₃ (Nitric acid)

4. In which direction the buoyant force acts on an object ?

Sol. Vertically upward

5. Which particles take part during chemical combination ?

Sol. Valence shell electrons.

(27)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. In which medium phenolphthalein is used as an indicator ?

Sol. Basic medium

2. What is the value of equilibrium constant K for the reaction H₂O H_{+ OH at 25}0_{C ?}

Sol. K = 10–14

3. In alumino-thermic process, what is the function of aluminium ?

Sol. As a reducing agent.

4. Which type of forces are present between the layers of graphite ?

Sol. Vander wall's forces.

5. What are the organic compounds called which have same molecular formula but different structural formula ?

Sol. Isomers

(28)

1. What is meant by strength of an acid.

Sol. Strength of an acid refers to the no. of moles of H+_{given by the acid per unit volume of its solution.}

2. What is the type of a reaction in which more reactive metal displaces a less reactive metal from its salt solution ?

Sol. Chemical displacement or redox reaction

3. How is plaster of paris prepared ?

Sol. Plaster of paris is prepared by heating of gypsum at 120ºC.

4. Why is crucible made of graphite ?

Sol. Because melting point of graphite is very high. (approx.3700ºC)

5. How is Glycerol purified ?

Sol. Vacuum distillation method

(29)

Subject : Chemistry DPP No. __ Class : VIII

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. What is the nature of aqueous solution of NH₄+ _? Sol. In an aqueous solution NH₄+_{will dissociate as : NH}

4

+ _NH

3 + H +

As NH₄+ _{gives a proton in its aqueous solution it acts as an acid.}

2. Which metal is found in liquid state ?

Sol. Mercury

3. What is the structure of diamond crystals ? Sol. Tetrahedral

4. Which fire extinguisher is used to extinguish fire caused by petrol at petrol pumps, ?

Sol. Foam type fire extinguisher

5. How is boiling point of a liquid affected with increase in atmospheric pressure ?

Sol. Boiling point will increases.

(30)

1. An acidic solution is prepared by dissolving 0.5 mol HCl in water, so that the final volume of the solution is 5.0 L. Determine the pH of the solution.

Sol. Moles of HCl present in 5L of solution = 0.5 Moles of HCl present in 1L of solution = 0.1 so, [H+_{] = 1}

× 10–1

 pH = 1

2. What is meant by refining of metal ?

Sol. The purification of the extracted metal is called as refining.

3. What is carbogen ?

Sol. Carbogen is a mixture of CO₂ and O₂ and is used for artificial respiration.

4. Why is mercury used in barometers primarily ?

Sol. It is heavy and therefore, the height of the mercury column that can be supported by atmospheric pressure is not very large.

5. Give one word for departure of individuals of same species from an area. Sol. Emigration

(31)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. What is thermite ?

Sol. Thermite is a mixture of Al powder and Fe₂O₃.

2. How will you test that air contains carbon dioxide ?

Sol. When air is passed through lime water, then lime water turn milky. Because CO₂ present in air reacts with Ca(OH)₂ to produce white precipitate of CaCO₃.

Ca(OH)₂ + CO₂ CaCO3 + H2O

Milky

3. Which gases cause acid rain ?

Sol. SO₂, NO₂

4. What is sex ratio ?

Sol. Number of females per 1000 males.

5. Give an example of double displacement reaction

-Sol. BaCl₂ + CuSO₄BaSO₄ + CuCl₂

(32)

1. Why is the aluminium used in thermite welding ?

Sol. Because Al has more affinity towards oxygen.

2. When is ozone day celebrated ?

Sol. September 16

3. Who gave vital force theory ?

Sol. Berzelius in 1808, gave vital Force theory. According to it organic compounds were formed by the living beings under some mysterious force.

4. What is the ratio of the diameter of the atom and the volume of the nucleus ?

Sol. 105

5. The pH of a solution of hydrochloric acid is 4. What is the molarity of solution ?

Sol. 10–4_M

(33)

Subject : Biology DPP No. __ Class : VIII

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. The famous book ‘micrographia’ was written by ...

Ans. Robert hooke

2. What do you mean by the term prokaryotic ?

Ans. prokaryotic have less develop nucleus without nuclear membrane & nucleolus.

3. Which cell organelle known as suicidal bags ?

Ans. Lysosome

4. Differentiate between an animal cell & plant cell.

Ans.

Plant Cell Animal Cell

Cell wall is present Cell wall is absent Plastids are found Plastids are absent One large vacuole Numerous tiny vacuoles

are found Centriole is absent Centriole is present

5. Which is the smallest living organism ?

Ans. Mycoplasma

01

(34)

1. Full name of ATP

Ans. Adenosine Triphosphate

2. Nuclear membrane reappears in which phase of mitotic cell division ?

Ans. Telophase

3. In which type of cell division number of chromosomes in daughter cell will be same as that of parent cell ?

Ans. Mitosis

4. Which organelle controlls the activity of cell ?

Ans. Nucleus

5. In humans the number of chromosomes in a haploid cell is –

Ans. 23

(35)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. In mammals thoracic and abdominal cavity is partitioned by a muscular structure known as

-Ans. Diaphragm

2. Which organ related to deoxygenated blood converted in oxygenated blood in human body.

Ans. Lungs

3. What is the function of epiglottis in man ?

Ans. Epiglottis prevents the entry of food particles in the trachea during the swallowing of food.

14. Indentify A,B,C

-Ans. (A) Aorta (B) Pulmonary veins (C) Right auricle

5. What is cytology ?

Ans. Study of Cell.

(36)

1. Which is the longest cell in a human body ?

Ans. Nerve Cell.

2. n which part of chloroplast is chlorophyll present ?

Ans. Grana

3. What is the mode of nutrition in fungi ?

Ans. Saprotrophic

4. Where is the site of light reaction

Ans. Grana of Chloroplast

5. Which is the site of Kreb cycle in cell ?

Ans. Mitochondria

(37)

Subject : Biology DPP No. __ Class : VIII

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. What are the end products of glycolysis ?

Ans. Pyruvic acid

2. Life span of human RBCs is of :

Ans. 120 days

3. The basic functional unit of human kidney is :

Ans. Nephron

4. In mammals fertilization takes place in

-Ans. Fallopian tube

5. Progesterone is secreted by

Ans. corpus luteum

(38)

1. Name the part of hind brain which takes part in regulation of respiration.

Ans. Pons varolli

2. Where cardiac muscles are found

Ans. Heart

3. Name the tissue where Haversian canals are found .

Ans. Bone

4. Which tissue found in sclereid cell ?

Ans. Sclerenchyma

5. Who proposed the theory of natural selection ?

Ans. Charles Darwin

(39)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. Total number of bones in the body of man is

Ans. 206

2. Identify the missing antibodies in given table

-Blood group Antigen present on RBCs Antibody in plasma

A A b

B B a

AB AB …..

O None …..

Table : Blood Group : Antigen & Antibody

Ans.

Blood group Antigen present on RBCs Antibody in plasm a

A A b

B B a

AB AB N one

O N one ab

Table : Blood Group : Antigen & Antibody

3. Who was Developed by oral vaccine of polio ?

Ans. Salk & Sabin

4. What is DPT stands ?

Ans. Diptheria, pertussis and tetanus vaccine

5. Name the bacterial disease

-Ans. TB

(40)

1. What is the full form of AIDS ?

Ans. Acquired Immuno Deficiency Syndrome.

2. Which of the disease is caused by dog bite ?

Ans. Rabies

3. Which type disease of haemophilia ?

Ans. Congenital disease

4. Name the vector and the causal organism of malaria.

Ans. Female anopheles & Plasmodium.

5. Which part of brain is more developed in man ?

Ans. Cerebrum

(41)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. Which cell organelle is absent in neuron ?

Ans. Centrioles

2. Human beings have ... cranial nerves.

Ans. 12 pairs

3. Which part of the brain is affected first in a drunk person

Ans. Cerebellum

4. Malpighian body is made up of

Ans. Bowman’s capsule and glomerulus

5. What is the function of Testes ?

Ans. Produce sperm

(42)

1. What is the fertilization ?

Ans. Fusion of nuclei of male and female gamete ?

2. Name the female reproductive part of a plant.

Ans. Ovary

3. Which is the smallest bone in man ?

Ans. Stapes

4. Which structure connects bone to skeletal muscle ?

Ans. Tendon

5. What are the raw materials required for photosynthesis ?

Ans. CO₂& H₂O

(43)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. Who published the massive three-volume work, A History of British India ?

Ans. James Mill

2. During British period, in which year the Supreme Court was established ?

Ans. 1775

3. At 12 noon of December 21, you observe that you cast no shadow as you stand in bright sunlight. So you must be somewhere near to which latitude ?

Ans. The Tropic of Capricorn

4. By what name the imaginary lines joining places of equal rainfall on the map are called ? Ans. Isohyets

5. Which Constitution has inspired the Indian concepts of rule of law, parliamentary system and lawmaking procedure?

Ans. British Constitution

6. If the Lok Sabha rejects the policy of the government on a particular issue, who must accept the responsibility, and resign ?

Ans. Whole Council of Ministers

Subject : Social Science DPP No. 1 Class : VIII

(44)

1. Who introduced the Mahalwari Settlement ?

Ans. Holt Mackanzie

2. Type of cultivation in which farmer left the land after two or three years of cultivation –

Ans. Shifting agriculture

3. Name the layer of earth made of mixed metals and silicates.

Ans. Mantle

4. In which layer of the atmosphere, the supersonic aircraft finds it most convenient to fly ? Ans. Stratosphere

5. How many members of a State Legislative Councils are elected by the local government bodies like the Zila Parishad, the Municipalities and the Municipal Corporations ?

Ans. One-third

6. Who administers the oath to a High Court judge ?

(45)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. Where did the sepoys break out in open revolt on May 10, 1857 ?

Ans. Meerut

2. Who organised a Durbar in Delhi to acknowledge Queen Victoria as the Empress of India?

Ans. Viceroy Lytton

3. Through which continent does the Tropic of Cancer, Tropic of Capricorn and Equator pass ?

Ans. Africa

4. Which is the most saline sea in the world ? Ans. Dead sea

5. Which Fundamental Right is known as a 'Guard of Democracy’ ? Ans. Right to Constitutional Remedies

6. Who fixes and announces the dates of the elections in our country ? Ans. Election Commission

(46)

Subject : Social Science DPP No. 4 Class : VIII 1. In which year the tricolour flag of the Indian National congress was adopted ?

Ans. 1931

2. Who founded Asiatic Society of Bengal ?

Ans. William Jones

3. On which river's bank Allahabad, Kanpur, Varanasi, Lucknow, Patana and Kolkata are situated ?

Ans. Ganga

4. Name the Alluvial triangular tract formed at the mouth of a river. Ans. Delta

5. What is the minimum age for a person to be qualified for standing in a panchayat election ? Ans. 21 years

6. Which institution works at International level for the betterment of Health, Nutrition and Education of Children ?

(47)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. In which year Dayanand Saraswati founded Arya Samaj ? Ans. 1875

2. Name the author of the book "Humayu Nama'. Ans. Gulbadan Begum

3. The formation of which soil results from the leaching away of the siliceous matter of the rocks ? Ans. Laterite soil

4. What type of climate India has ? Ans. Monsoonal type

5. How much reservation for women in all the legislatures of India has been proposed ?

Ans. 33 %

6. Which emergency is going to be imposed if the Governor of a State writes a letter asking for emergency on the basis of failure of constitution in that State ?

(48)

1. Which is the important epic written by Jaysi ? Ans. Padmawat

2. By which Act was the Governor General given the authority over the presidencies of Bombay and Madras? Ans. Pitt's India Act of 1784

3. In which state is the Simlipal Bio Reserve located ? Ans. Orissa

4. Name India's first mobile offshore drilling platform. Ans. Sagar Samrat

5. Name the carbon compounds which are responsible for the depletion of Atmospheric Ozone layer. Ans. Cholorofluorocarbons (CFCs)

6. On which day FAO was founded, whcih is also observed as World Food day every year ? Ans. 16 October

(49)

N T S E S TAGE -I II

IN T E RV IE W DP P

S E S S I O N : 2 0 1 0 - 1 1

1. Who banned female infanticide in india ? Ans. William Bentinck

2. Name the lady who lead the Revolution of 1857 in Lucknow. Ans. Hazarat Mahal

3. Which city is known as the 'Lankashire of the East' ?

Ans. Surat

4. Which canal connects the Mediterranian sea and Red sea ? Ans. Suej Canal

5. Name the Prime Minister of India who formulated the policies of Panchsheel. Ans. Pt. Jawahar Lal Nehru

6. Which country played a major role in liberating Bangladesh from Pakistan in 1972 ?

(50)

1. Who gave the two nation theory ? Ans. Mohammad Ali Jinnah

2. In which year the settlers of the 13 colonies of America adopted the Declaration of Independence written by Thomas Jefferson ?

Ans. 4 July 1776

3. Which country has the highest percentage of its land under cultivation in the world ?

Ans. India

4. Crops requiring different nutrients are grown in succession to give the soil some time to regain the nutrients lost in earlier seasons. This is called as