Page 107 - CITS - WCS - Mechanical

WORKSHOP SCIENCE - CITS

Assignment

1 What current flows through the bulb of a 3.00-V flashlight when its hot resistance is 3.60Ω3.60Ω?
Solution
0.833 A
2 What is the resistance of a 20.0-m-long piece of 12-gauge copper wire having a 2.053-mm diameter?
Solution
0.104 Ω

3 What is the effective resistance of a car’s starter motor when 150 A flows through it as the car battery applies
11.0 V to the motor?
Solution
7.33×10−2Ω

1 What will be the resistance if 10 resistors of 10 ohm each is connected in series
(A)100 ?
(B)1 ?
(C) 0.1 ?
(D)10 ?.
ANSWER-A
2 Resistivity of a wire depends on

(A) length
(B) material
(C) cross section area
(D) All of the above.
ANSWER-B
3 Which of the following is not the same as watt?
(A) joule/sec
(B) amperes/volt

(C) amperes x volts
(D ) ( amperes )2 x ohm.
ANSWER-B
4 Ohm’s law is not applicable to
(A) DC circuits
(B) high currents

(C) small resistors
(D) semi-conductors.
ANSWER-D
5 A wire of resistance R has it length and cross-section both doubled. Its resistance will become
(A) 4 R
(B)2 R
(C) R
(D) R / 4.

ANSWER-C

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CITS : WCS - Mechanical - Exercise 9