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A and B points are present on the axis o...

A and B points are present on the axis of a bar magnet of length 3 cm and at 24 cm and 48 cm respectively, from the opposite direction of the centre. The ratio of magnetic fields at these points is ...... .

A

`8:1`

B

`4:1`

C

`3:1`

D

`1: 2 sqrt2`

Text Solution

Verified by Experts

The correct Answer is:
A

The intensity of magnetic field on a axis of small magnet ` B alpha (1)/( z^3)`
`therefore (B_1)/( B_2) = ((z_2)/(z_1) )^(3)`
`therefore (B_1)/(B_2) = ((48)/( 24))^(3) = (2)^(3)`
`therefore (B_1)/( B_2) = (8)/(1)`
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KUMAR PRAKASHAN-MAGNETISM AND MATTER-SECTION D Multiple Choice Questions (MCQs) (MCQs From .DARPAN. Based On Textbook) Bar Magnet, Bar Magnet as Equivalent Solenoid
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