IECEP Electronics and Communications Engineering Quiz 2012

(1)

IECEP-Manila Form 1 S.2012 TEST QUESTIONS 1. Please Use One Page per Question. 2. Fill-out all needed information.

3. Submissions with incomplete data will not be considered.

Name of School Technological University of the Philippines - Manila Signature over Printed

Name of the Coach/Adviser

Engr. Edmon O. Fernandez

Please indicate the subject: () Mathematics

(/) General Engineering and Applied Science () Electronics Engineering

() Electronics System & Technologies

QUESTION: On the basis of magnetic response, superconducting materials while in the superconducting state, are completely diamagnetic; that is, all of an applied magnetic field will be excluded from the body of material, a phenomenon known as the ___________.

ANSWER: Meissner effect

SOLUTION ( IF PROBLEM -SOLVING)

Reference: Materials Science and Engineering, An Introduction, 7th_ed, William D. Callister, pg 105

(2)

QUESTION: In environmental engineering, this refers to the SI measure of source strength or total radioactivity, and is defined as one disintegration per second.

ANSWER: Becquerel

Reference: Environmental Engineering 4th_{edition, Weiner and Matthews,} page 319

(3)

QUESTION: In physics, this refers to a situation in which a very small change in one place can amplify into a large change somewhere else.

ANSWER: Butterfly effect

(4)

QUESTION: A thin metal can is rolls down an inclined plane and reach the bottom with the speed of 4.43 m/s. Determine the speed at the bottom when the can is full.

ANSWER: 5.12 m/s

Reference: College Physics 5th_{Ed. by Weber, Manning, White and Weygand,} pp. 126-127

(5)

QUESTION: The bob of a pendulum has its rest point 1.00 m below the support. The bob is pulled aside until the string makes an angle of 15 degrees with the vertical. Upon release, with what speed does the bob swing past its rest point?

ANSWER: 0.82 m/s

Reference: College Physics 5th_{Ed. By Weber, Manning, White and Weygand,} p. 92

(6)

() General Engineering and Applied Science (/) Electronics Engineering

QUESTION: It states that at any point P the magnitude of the magnetic field

intensity produced by the differential element is proportional to the product of the current, the magnitude of the differential length, and the sine of the angle lying between the filament and a line connecting the filament to the point P where the field is desired.

ANSWER: Law of Biot-Savart

Reference: Engineering Electromagnetics (5th Edition) by William H. Hayt, Jr., pp

(7)

QUESTION: When controlling the action of a relay, one of the cheapest but most

effective ways to protect the switching system is to place a capacitor across the terminals of the coil. This capacitor is commonly called _____?

ANSWER: Snubber

Reference: Electronic Devices and Circuit Theory (10th Edition) by Robert L.

(8)

QUESTION: A 1500-turn solenoid produces 600,000 maxwells when excited by a

current of 2.5 amp. Calculate the inductance.

ANSWER: 3.6 Henrys

(9)

QUESTION: Aseries of specb-aP lines obtained by the scattering of electrons when an electron beam is directed against a crystalline solid. The pattern may be interpreted to yield information on the structure of the crystal and its mechanical perfection.

ANSWER: Kikuchi Lines

(10)

QUESTION: Simplify the Boolean expression to a minimum number of literals: xy’ +

y’z’ + x’z’

ANSWER: xy’ + x’z’

xy’ + y’z’ + x’z’ = xy’(z + z’) + y’z’(x+ x’) + x’z’(y + y’)

= xy’z + xy’z’ + y’z’x + y’z’x’ + x’z’y+ x’z’y’

= xy’z + xy’z’ + x’y’z’ + x’yz’ = xy’(z + z’) + x’z’(y + y’)

= xy’ + x’z’

(11)

() General Engineering and Applied Science () Electronics Engineering

(/) Electronics System & Technologies

QUESTION: Informations transmitted to the mobile phone, either subscribed or unsolicited messages, without a user request and are initiated by the server of the content provider.

ANSWER: Push messages

Reference:Section 2 NTC Memorandum Circular No. 03-02-2005, Rules and Regulations on Broadcast Messaging Service

(12)

QUESTION: It is a wireless networking scheme that competes with both 802.11 and bluetooth schemes. It uses frequency hopping ang spread spectrum communication at 2.4GHz and is intended for small home networks.

ANSWER: Home RF

(13)

QUESTION: It is a wireless technology that enables a variety of contactless and proximity-based applications, such as payments, information retrieval, mobile marketing and device pairing. It has an operating range of 10 cm or less using the 13.56MHz frequency band. There are currently three user modes defined for its operation: 1) Card emulation, 2) Tag reading, and 3) Peer-to-peer (P2P). These modes are based on several ISO/IEC standards, including ISO14443 A/B, ISO15693 and ISO18092.

ANSWER: NFC (Near Field Communication) SOLUTION ( IF PROBLEM -SOLVING)

(14)

QUESTION: Assume we need to download text documents at the rate of 100 pages per minute. What is the required bit rate of the channel?

ANSWER: 1.636 Mbps

A page is an average of 24 lines with 80 characters in each line. If assume that one character requires 8 bits, the bit rate is:

Bit rate = (100)(24)(80)(8) = 1 636 000 bps Bit rate = 1.636 Mbps

Reference: Data Communications and Networking by Behrouz A. Forouzan, 4th ed., p73

(15)

QUESTION: Determine the fade margin for the following conditions: distance between sites, d = 50 km; frequency, f = 1.8GHz; very dry mountainous terrain and a reliability of 99.9999%.

ANSWER: 36. 25 dB

SOLUTION ( IF PROBLEM -SOLVING) Fm = 30logD + 10log(6ABf) – 10log(1-R) – 70

Where A = roughness factor, 0.25 for mountainous terrain

B = factor to convert a worst-month probability to an annual probability, 0.125 for very dry mountainous terrain

= 30log(50) + 10log[(6)(0.25)(0.125)(1.8) – 10log(1-0.999999) – 70 Fm = 36.25 dB

(16)

Please indicate the subject: (/) Mathematics

QUESTION: The geometric mean of several positive numbers is smaller than the arithmetic mean of these numbers.

ANSWER: Cauchy’s Mean Theorem SOLUTION ( IF PROBLEM -SOLVING)

(17)

QUESTION: A line segment joining the vertex of a triangle to any given point on the opposite side is called?

ANSWER: Cevian

(18)

QUESTION: It states that if L{F1(t)} = L{F2(t)}, then F1(t) – F2(t) = N(t), where N(t) is a null function. That is, an inverse Laplace transform is unique for the addition of an

arbitrary null function.`

ANSWER: Lerch’s Theorem

Reference:Elementary Differential Equations 7th edition by Earl D. Rainville & Phillip E. Bedient, p. 210

(19)

QUESTION:

Find the shortest distance from the point

to the plane

ANSWER: 4/3 units

√ But

It follows that if is minimum, is also minimum.

Applying maxima-minima for partial derivatives, we have:

Solving the two equations simultaneously and using we obtain

Hence,

√

(20)

QUESTION:

A lumber mill cuts rectangular beams from circular logs. If the

diameter of the log is 16 inches and the cross-sectional area of the beam is

120 square inches, find the dimensions of the cross section of the beam.

Give the exact values.

ANSWER: √ √

Let a and b be the dimensions

√ √ √ √ √ Hence, √ √ √ √

Reference:Precalculus: Functions and Graphs, pg.80, 5th edition, Barnett, Zeigler and Bayleen