SCIENCE AND TECHNOLOGY – Math-Science Dears

SCIENCE AND TECHNOLOGY – Chapter 4

Magnetic Effects of Electric Current

1 / 15

A current flows in a wire running between the S and N poles of a magnet lying horizontally as shown in the figure below:

The force on the wire due to the magnet is directed:

From N to S

From S to N

Vertically downwards

Vertically upwards

2 / 15

The frequency of electricity produced by DC generator is equal to

0 Hz

50 Hz

100 Hz

200 Hz

3 / 15

Which of the following diagrams correctly shows the magnetic field produced by a current- carrying wire?

4 / 15

An electric motor is a device which transforms

Mechanical energy into electrical energy

Electrical energy into mechanical energy

Kinetic energy into potential energy

Electrical energy into Potential energy

5 / 15

The shape of the magnetic field lines produced by a current carrying conductor are:

Straight lines

Concentric circles

Concentric ellipse

Concentric parabolas

6 / 15

A coil of insulated copper wire is connected to a galvanometer forming a loop and a magnet is:
A: Held stationary
B: Moved away along its axis
C: Moved towards along its axis
There will be a induced current in:

A only

A and B only

B and C only

A, B and C

7 / 15

If two circular coils can be arranged in any of the three situations as shown in the diagrams below, then their mutual induction will be:

Maximum in situation a

Maximum in situation b

Maximum in situation c

The same in all situations

8 / 15

A fuse should always be placed in the

Live wire of the main circuit

Neutral wire of the main circuit

Earth wire of the main circuit

Bothe live and neutral wire of the main circuit

9 / 15

A positive charge is moving towards a person. The direction of magnetic field lines will be in

Clockwise direction

Anticlockwise direction

Vertically upward direction

Vertically downward direction

10 / 15

An induced emf is produced when a magnet is moved into a coil. The magnitude of induced emf does not depend on:

The speed with which the magnet is moved

The number of turns of the coil

The resistivity of the wire of the coil

The strength of the magnet

11 / 15

The force exerted on a current carrying wire placed in a magnetic field is zero when the angle between wire and the direction of magnetic field is:

45°

60°

90°

180°

12 / 15

A current carrying conductor is held in exactly vertical direction. In order to produce a clockwise magnetic field around the conductor, the current should be passed in the conductor:

From top to bottom

From left to right

From bottom to top

From right to left

13 / 15

A soft iron bar is inserted inside a current-carrying solenoid. The magnetic field inside the solenoid:

Will decrease

Will increase

Will become zero

Will remain the same

14 / 15

The north pole of Earth’s magnet is in the:

Geographical South

Geographical East

Geographical West

Geographical North

15 / 15

The magnetic field lines outside a bar magnet:

Originate from the South pole and end at its North Pole

Originate from the North pole and end at its East Pole

Originate from the North Pole and end at its South Pole

Originate from the South pole and end at its West Pole

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