NUMS T8 Electromagnetism & Electromagnetic induction

Magnetic 🧲 field lines are

• Real

• Imaginary

• From south to north pole

• None

The direction of current in conductor is given then In which direction conductor "B" will move?

• left

• inward

• right

• outward

Two parallel long wires carry the same current and repel each other with a force F per unit length. If both these currents are doubled and the wire separation tripled, the force per unit length becomes:

• 2F/9

• 4F/9

• 2F /3

• 4F/3

If "L" is length of a wire with cross sectional area A carrying "n" number of charge carriers per unit volume moving with velocity v, then current through it is given as:

• nAqv

• Aqv/n

• nAq/v

• qv/nA

With a force of 1mN. If both currents are doubled, the force of attraction will be:

• lmN

• 4mN

• 5mN

• 0.25mN

Two long straight wires are parallel and carry current in the same direction. The currents are 8.0 and 12A and the wires are separated by 0.4 cm. The magnetic field in tesla at a point midway between the wires is:

• 0

• 4.0 x 10-4

• 8.0 x 10-4

• 12 x 10-4

If current carrying conductor is placed perpendicular to the magnetic field, the force experienced by it will be:

• zero

• ILB

• maximum

• ILB cos theta

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

• Maximum

• Minimum

• Zero

• infinity

The magnetic field a distance 2 cm from a long straight current carrying wire is 2.0 x 10^-5 T. The current in the wire

• 0.16A

• 2.0 A

• 1.0 A

• 4.0 A

The magnetic field outside a long straight current carrying wire depends on the distance "R" from the wire according to:

• R

• 1/R2

• 1/R

• 1/R3