4. Moving charges and magnetism

In a certain region of space, electric field E and magnetic field B are perpendicular to each other. An electron enters perpendicularly to both the fields and moves undeflected. The velocity of electron is

• E/B

• B/E

• E x B

• E.B

A rectangular coil ABCD is placed near a long straight current carrying straight wire as shown. What is the net force on the rectangular coil?

• 25 x 10^-7 N towards the wire

• 25 x 10^-7 N away from the wire

• 35 x 10^-7 N, towards the wire

• 35 x 10^-7 N, away from the wire

To convert a moving coil galvanometer into on ammeter of given range, we must connect:

• A suitable low resistance in series

• A suitable low resistance in parallel

• A suitable high resistance in parallel

• A suitable high resistance in series

Current sensitivity of a galvanometer can be increased by decreasing :

• Magnetic field B

• number of turns N

• torsional constant K

• Area A

Currents of 10 A and 2 A are flowing in opposite directions through two parallel wires A and B respectively. If the wire A is infinitely long and wire B is 2 m long, then force on wire B which is situated at 10 cm from A, is

• 8 x 10 ^ ^-5 N

• 6 x 10 ^^-5 N

• 4 x 10 ^ ^-5 N

• 2 X 10 ^ ^-5 N

A circular coil of radius 10 cm is placed in X - Y plane, a constant current of 10 A is flowing in it in clockwise sense. The magnitude and direction of magnetic field at the centre are

• 2 $\pi$ $\times$ 10^-5 T along z - axis

• 2 $\pi$ $\times$ 10^-5 T along $-$ z axis

• 2 $\times$ 10^-5 T along z - axis

• 2 $\times$ 10^-5 T along $-$ z axis

A wire is kept along north - south direction and a constant current is flowing in it in north to south direction. What will be the direction of the force on the wire if it is placed in constant magnetic field along west to east direction:

• Downwards

• Upwards

• Along left side

• Along right side

The resistance of an ideal voltmeter should be ----

A charge particle is moving undeflected in a uniform electric and magnetic fields, now the magnetic field is switched off, the trajectory of the particle will be

• circular

• helical

• straight line

• elliptical

What causes magnetism?

• the sun

• moving neutrons

• moving charges

• friction

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5