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Current Electricity

Question
CBSEENPH12039618
Wired Faculty App

A long straight wire of radius ‘a’ carries a steady current i. The current is uniformly distributed across its cross section. The ratio of the magnetic field at a/2 and 2 a is 

  • 1/4

  • 4

  • 1

  • 1/2

Solution

C.

1

straight B 2 straight pi straight a over 2 space equals space straight mu subscript 0 straight i over πa squared open parentheses πa squared over 4 close parentheses straight B subscript 1 space equals fraction numerator straight mu subscript 0 straight i over denominator 4 πa end fraction space... left parenthesis straight i right parenthesis straight B subscript 2 space 2 straight pi space left parenthesis 2 straight a right parenthesis space equals space straight mu subscript 0 space straight i straight B subscript 2 space equals fraction numerator straight mu subscript 0 space straight i over denominator 4 space πa end fraction space space space... space space left parenthesis ii right parenthesis straight B subscript 1 over straight B subscript 2 space equals 1

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?

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