KVPY Stream SB-SX (Class 12 & 1st Year B.Sc.) Physics: Questions 78 - 80 of 268

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Question number: 78

» Current Electricity » Temperature Dependence of Resistance

Appeared in Year: 2012

MCQ▾

Question

A steady current Ι flows through a wire of radius r, length L and resistivity ρ. The current produces heat in the wire. The rate of heat loss in a wire is proportional its surface area. The steady temperature of the wire is independent of

Choices

Choice (4) Response

a.

L

b.

r

c.

I

d.

p

Question number: 79

» Electrostatics » Capacitors

Appeared in Year: 2012

MCQ▾

Question

The capacitor of capacitance C in the circuit shown is fully charged initially, Resistance is R.

Circuit diagram of resistance and capacitor

Circuit Diagram of Resistance and Capacitor

In figure RC circuit diagram is shown.

After the switch S is closed, the time taken to reduce the stored energy in the capacitor to half its initial value is:

Choices

Choice (4) Response

a.

Cln 2

b.

2RCln2

c.

RCln22

d.

RC2

Question number: 80

» Physics and Measurement » Accuracy and Precision of Measuring Instruments

Appeared in Year: 2011

MCQ▾

Question

Four students measure the height of a tower. Each student uses a different method and each measures the height many different times. The data for each are plotted below. The measurement with highest precision is,

Choices

Choice (4) Response

a.

Graph of Number of Trials verses Height Choice A

Graph of Number of Trials Verses Height Choice A

in figure graph of number of trials verses height is shown.

b.

 Graph of Number of Trials verses Height Choice B

Graph of Number of Trials Verses Height Choice B

in figure graph of number of trials verses height is shown.

c.

 Graph of Number of Trials verses Height Choice C

Graph of Number of Trials Verses Height Choice C

In figure graph of number of trials verses height is shown.

d.

Graph of Number of Trials verses Height Choice D

Graph of Number of Trials Verses Height Choice D

In figure graph of number of trials verses height is shown.

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