12th Class Physics MCQS Chapter 3

e/m=

Br/V

VB/r

Vr/B

v/Br

The force on a charge particle moving parallel to magnetic field is:

Zero

None of these

Maximum

Minimum

One weber is equal to:

N.A ²/m

N.m²/A

N.m/A

N.A/m

An electron moves at 2 x 10² m/sec perpendicular to magnetic field of 2T what is the magnitude of magnetic force:

4 x 10⁶ N

3.6 x 10^-24 N

6.4 x 10^-17 N

1 x 10^-6 N

Ampere’s law is applicable to:

To any closed path

Rectangular path

Circular path

Nonwe of these

The torque in the coil can be increased by increasing:

No. of turns

Current and magnetic field

All of the above

Area of coil

A soft iron cylinder is placed  inside coil galvanometer to:

Make field circular and strong

Make field radial and weak

Make field radial and strong

All of above

The vector sum of electric force and magnetic force is called:

Deflecting force

Lorentz force

Faraday’s force

Newton force

The permeability of free space is measured in

wb A/m

Am/wb

m/wbA

wb/Am

The unit of magnetic induction is:

Weber

NAm^-1

Weber metre

Tesla