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Current Electricity

Question
CBSEENPH12039869
Wired Faculty App

In an ammeter 0.2 % of the main current passes through the galvanometer. If resistance of galvanometer is G, the resistance of ammeter will be,

  • 1/499 G

  • 499/500 G

  • 1/500 G

  • 500/499 G

Solution

A.

1/499 G

For ammeter,

0.0002 I x G = 0.998 I x rg

rg = fraction numerator 0.002 over denominator 0.998 end fraction G
That is,
straight r subscript straight g space equals space 0.002004 space straight G space equals space 1 over 499 straight x space straight G
Resistance of ammeter is approximately equal to resistance of shunt rB.

Some More Questions From Current Electricity Chapter

What conclusion can you draw from the following observations on a resistor made of alloy manganin?

Current A

Voltage V

Current A

Voltage V

0.2

0.4

0.6

0.8

1.0

2.0

3.94

7.87

11.8

15.7

19.7

39.4

3.0

4.0

5.0

6.0

7.0

8.0

59.2

78.8

98.6

118.5

138.2

158.0

Answer the following questions:
A steady current flows in a metallic conductor of non-uniform cross-section. Which of these quantities is constant along the conductor: current, current density, electric field, drift speed?

Answer the following questions:
Is Ohm’s law universally applicable for all conducting elements? If not, give examples of elements which do not obey Ohm’s law.

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