CBSE Class 12 Physics Current Electricity Quiz 5

1. Which of the following has a negative temperature coefficient of resistance?

A Tungsten B Carbon C Nichrome D Platinum

2. An electric heating element consumes 500 W, when connected to a 100 V line. If the line voltage becomes 150 V, the power consumed Will be:

A 500 W B 750 W C 1000 W D 1125 W

3. A uniform w ire connected across a supply produces heat H per second. If wire is cut into three equal parts and all the parts are connected in parallel across the same supply, the heat produced per second will be :

A \(\frac{H}{9}\) B 9 H C 3 H D \(\frac{H}{3}\)

4. In India electricity is supplied fordomestic use at 220 V. It is supplied at 110 V in U.S.A. If the resistance of a 60 W bulb use in India is R. the resistance of a 60 W bulb for use in USA will be:

A 2 R B R C R/2 D R/4

5. Two bulbs 25 W, 220 V and 100 W, 220 V are given. Which has higher resistance?

A 25 W B 100 W C both bulbs have equal resistance D resistance of bulbs can not be compared

6. Potentiometer measures the potential difference more accurately than a voltmeter because:

A It has a wire of high resistance B It has a wire of low resistance C It does not draw current from external circuit D It draws heavy current from external circuit

7. In a Wheatstone bridge, the resistance each arm is 10 Ω. If the resistance galvanometers is also 10 Ω, then effective resistance of the bridge will be :

A 40 Ω B 20 Ω C 10 Ω D 5 Ω

8. The resistance of an aluminium wire is/i. It is stretched to /i times its original length. Its new resistance will be :

A nr B n²r C \(\frac{n^2}{r}\) D \(\frac{r}{n^2}\)

9. A wire P is half the diameter and half the length of a wire Q of similar material. The ratio of resistances of P to that 0 is:

A 4 : 1 B 8 : 1 C 2 : 1 D 1 : 2

10. What is the resistance across A and B in the network in Fig.?

A R B 2 R C \(\frac{R}{2}\) D 6 R