Current Electricity-Electrical Resistance (KVPY Stream-SA (Class 11) Physics): Questions 1 - 2 of 2

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Question number: 1

» Current Electricity » Electrical Resistance

Short Answer Question▾

Write in Short

Consider the two circuits P and Q, shown below, which are used 20 measure the unknown resistance R.

Circuit diagrams P and Q

Circuit Diagrams P and Q

In figure two circuit diagrams P and Q are shown. In circuit P voltmeter is use to measuring voltage across only R, and in circuit Q voltmeter use for measuring voltage across R and Ammeter.

In each case, the resistance is estimated by using Ohm’s law Rest=VI , Where V and I are the readings of the voltmeters and the ammeters respectively. The internal resistances of voltmeter and ammeter are R V and R A, such that R A < < R < < R V.

The internal resistance of the battery may be ignored. The absolute error in the estimate of the resistance is denoted by δ R =| R - Rest| .

(a) Express δ R P in terms of the given resistance values

(b) Express δ R Q in terms of the given resistance values

(c) For what value of R will δ R P ≈ δ R Q

Question number: 2

» Current Electricity » Electrical Resistance

Appeared in Year: 2011

MCQ▾

Question

A cylindrical copper rod has length L and resistance R. If it is melted and formed into another rod of length 2L, than the resistance will be

Choices

Choice (4) Response
a.

8R

b.

R

c.

4R

d.

2R

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