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Current Electricity

Question
CBSEENPH12039498
Wired Faculty App

The coercivity of a small magnet where the ferromagnet gets demagnetized is 3 x 103Am-1.The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetized when inside the solenoid, is

  • 30 mA

  • 60 mA

  • 3 A

  • 6 A

Solution

C.

3 A

For solenoid, the magnetic field needed to be magnetised the magnet,
B =μonl
Where, n = 100
l = 10 cm = 10/100 m  = 0.1m
3 space straight x space 10 cubed space equals space fraction numerator 100 over denominator 0.1 end fraction space straight x space l l space equals 3 straight A

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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