Home
Class 12
PHYSICS
The coercitivity of a small magnet where...

The coercitivity of a small magnet where the ferromagnet gets demagnetized is `3 xx 10^(3) Am^(-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 :

A

30mA

B

60mA

C

3A

D

6A

Text Solution

Verified by Experts

The correct Answer is:
C
For solenoid , the magnetic field needed to be magnetised the magnet , `B=mu_(0)nl`
[ where , `n=100, l=10 cm =(10)/(100)m=0.1m`]
`implies 3 xx 10^(3) =(100)/( 0.1) xx l `
`implies l=3A `
Promotional Banner

Topper's Solved these Questions

  • MAGNETISM-II

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise MHT CET Corner|8 Videos

  • MAGNETISM-II

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise Exercise 1|24 Videos

  • MAGNETISM-I

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise Exercise 2|25 Videos

  • MEASUREMENTS

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise EXERCISE 2 (MISCELLANEOUS PROBLEMS)|17 Videos

Similar Questions

Explore conceptually related problems

A current of 2 A flows in an air core solenoid of length 1 m and number of turns 1000. What is the magnetic flux density inside the solenoid?

A thin solenoid of length 0.4 m and having 500 turns of wire carries a current 1A ,then find the magnetic field on the axis inside the solenoid.

A solenoid of length 0.5 m has a radius of 1 cm and is made up of 500 turns. It carries a current of 5 A. The magnetic field inside the solenoid is

The coercive force for a certain prmanent magnet is 4.0 xx 10^4 A m^(-1) . This magnet is placed inside a long solenoid of 40 turns/cm and a current is passed in the solenoid to demagnetize it completely. Find the current.

The coercivity of a certain permanent magnet is 4.0xx10^(4)Am^(-1) . The magnet is placed insider a solenoid 20cm long having 700 turns and a current is passed in the solenoid to demagnetise it completely. Find the current

There is a magnetic material of coercitivy 2xx10^(3)Am^(-1) . What current should flow through solenoid of length 15 cm having 150 turns to demagnetise the substance completely?

The coercivity of a certain permanent magnet is 4*0xx10^4Am^-1 . This magnet is placed inside a solenoid 15cm long and having 600turns . Calculate the current required to demagnetise the magnet completely.

A bar magnet has coercivity 4xx10^(3) Am^(-1) . It is desired to demagnetise it by inserting it inside a solenoid 12 cm long and having 60 turns. The current that should be sent through the solenoid is