Extra 40 multiple-choice questions (MCQs) with answers on the Chapter:12 "Magnetic Effects of Electric Current" chapter for Class 10 CBSE Science:

 

The region around a magnet where its influence can be felt is called a:

 

(a) Magnetic field

 

(b) Electric field

 

(c) Gravitational field

 

(d) Electromagnetic wave

 

Ans: (a) Magnetic field

 

The SI unit of magnetic field strength is:

 

(a) Tesla

 

(b) Gauss

 

(c) Ampere

 

(d) Newton

 

Ans: (a) Tesla

 

The direction of a magnetic field around a current-carrying conductor is given by:

 

(a) Fleming’s Left-Hand Rule

 

(b) Right-Hand Thumb Rule

 

(c) Fleming’s Right-Hand Rule

 

(d) Ampere’s Rule

 

Ans: (b) Right-Hand Thumb Rule

 

The magnetic field inside a long current-carrying solenoid is:

 

(a) Zero

 

(b) Uniform

 

(c) Stronger at the ends

 

(d) Weak

 

Ans: (b) Uniform

 

The strength of the magnetic field due to a current-carrying conductor is:

 

(a) Directly proportional to distance

 

(b) Inversely proportional to distance

 

(c) Independent of distance

 

(d) None of these

 

Ans: (b) Inversely proportional to distance

 

What happens to the magnetic field if the current through a conductor is reversed?

 

(a) It remains the same

 

(b) It reverses its direction

 

(c) It increases in strength

 

(d) It decreases in strength

 

Ans: (b) It reverses its direction

 

The right-hand thumb rule helps to determine:

 

(a) Direction of force on a conductor

 

(b) Direction of magnetic field around a conductor

 

(c) Direction of induced current

 

(d) Direction of motion of a conductor

 

Ans: (b) Direction of magnetic field around a conductor

 

The Earth’s magnetic field is caused due to:

 

(a) Magnetic materials in the core

 

(b) Earth’s rotation

 

(c) Electric currents in the molten outer core

 

(d) Gravitational forces

 

Ans: (c) Electric currents in the molten outer core

 

The magnetic field around a straight current-carrying conductor is:

 

(a) Circular

 

(b) Rectangular

 

(c) Concentric circles

 

(d) Parallel lines

 

Ans: (c) Concentric circles

 

The field lines around a current-carrying straight conductor are:

 

(a) Circular and perpendicular to the conductor

 

(b) Parallel to the conductor

 

(c) Radial from the conductor

 

(d) None of these

 

Ans: (a) Circular and perpendicular to the conductor

 

Which of the following produces a uniform magnetic field?

 

(a) A current-carrying straight conductor

 

(b) A circular loop

 

(c) A solenoid

 

(d) A bar magnet

 

Ans: (c) A solenoid

 

The core of an electromagnet is usually made of:

 

(a) Copper

 

(b) Aluminium

 

(c) Soft iron

 

(d) Steel

 

Ans: (c) Soft iron

 

A solenoid behaves like a:

 

(a) Bar magnet

 

(b) Coil

 

(c) Both (a) and (b)

 

(d) None of these

 

Ans: (c) Both (a) and (b)

 

The device that converts electrical energy into mechanical energy is:

 

(a) Transformer

 

(b) Electric motor

 

(c) Generator

 

(d) Battery

 

Ans: (b) Electric motor

 

The device that converts mechanical energy into electrical energy is:

 

(a) Motor

 

(b) Generator

 

(c) Transformer

 

(d) Battery

 

Ans: (b) Generator

 

The principle of an electric motor is based on:

 

(a) Fleming’s Left-Hand Rule

 

(b) Fleming’s Right-Hand Rule

 

(c) Right-Hand Thumb Rule

 

(d) Ampere’s Law

 

Ans: (a) Fleming’s Left-Hand Rule

 

The split ring in a motor is used to:

 

(a) Increase speed

 

(b) Reverse the direction of current

 

(c) Reverse the direction of rotation

 

(d) Reduce current

 

Ans: (c) Reverse the direction of rotation

 

A commutator in an electric motor is used to:

 

(a) Provide a path for current

 

(b) Reverse current direction periodically

 

(c) Increase the voltage

 

(d) Decrease resistance

 

Ans: (b) Reverse current direction periodically

 

The rule used to find the direction of force in a motor is:

 

(a) Right-Hand Thumb Rule

 

(b) Fleming’s Left-Hand Rule

 

(c) Fleming’s Right-Hand Rule

 

(d) Lenz’s Law

 

Ans: (b) Fleming’s Left-Hand Rule

 

The electric generator works on the principle of:

 

(a) Electromagnetic induction

 

(b) Electrostatic force

 

(c) Thermal conduction

 

(d) Mechanical force

 

Ans: (a) Electromagnetic induction

 

The phenomenon of inducing a current in a conductor due to a changing magnetic field is called:

 

(a) Electromagnetic induction

 

(b) Electric effect

 

(c) Magnetic force

 

(d) Electric induction

 

Ans: (a) Electromagnetic induction

 

The rule used to find the direction of induced current is:

 

(a) Fleming’s Right-Hand Rule

 

(b) Fleming’s Left-Hand Rule

 

(c) Right-Hand Thumb Rule

 

(d) Lenz’s Law

 

Ans: (a) Fleming’s Right-Hand Rule

 

The function of an earth wire in household circuits is:

 

(a) Increase voltage

 

(b) Provide a return path

 

(c) Prevent electric shocks

 

(d) Increase current flow

 

Ans: (c) Prevent electric shocks

 

A fuse in an electric circuit is used to:

 

(a) Increase voltage

 

(b) Prevent overloading

 

(c) Reduce current

 

(d) None of these

 

Ans: (b) Prevent overloading

 

The frequency of AC supply in India is:

 

(a) 50 Hz

 

(b) 60 Hz

 

(c) 30 Hz

 

(d) 40 Hz

 

Ans: (a) 50 Hz

 

Overloading in household circuits occurs when:

 

(a) Too many appliances are connected

 

(b) A single wire is used

 

(c) Switches are defective

 

(d) None of these

 

Ans: (a) Too many appliances are connected

 

A generator produces:

 

(a) Only AC

 

(b) Both AC and DC

 

(c) Only DC

 

(d) None of these

 

Ans: (b) Both AC and DC

 

 

34. The direction of the magnetic field inside a bar magnet is:

(a) From north to south
(b) From south to north
(c) Circular around the magnet
(d) Randomly oriented
Ans: (b) From south to north

 

35. Which of the following factors does NOT affect the strength of an electromagnet?

(a) Number of turns in the coil
(b) Strength of the current
(c) Type of core material
(d) Length of the wire used
Ans: (d) Length of the wire used

 

36. A current-carrying conductor placed perpendicular to a magnetic field experiences:

(a) No force
(b) A force in the direction of current
(c) A force perpendicular to both current and field
(d) A force along the magnetic field
Ans: (c) A force perpendicular to both current and field

 

37. The magnetic effect of current was first observed by:

(a) Ampere
(b) Oersted
(c) Faraday
(d) Newton
Ans: (b) Oersted

 

38. The function of brushes in an electric motor is to:

(a) Change the direction of current
(b) Maintain electrical contact between rotating and stationary parts
(c) Reduce energy losses
(d) None of the above
Ans: (b) Maintain electrical contact between rotating and stationary parts

 

39. What happens when a current-carrying conductor is placed in a magnetic field?

(a) It moves if the field is strong enough
(b) It gets heated up
(c) It gets magnetized permanently
(d) Nothing happens
Ans: (a) It moves if the field is strong enough

 

40. Lenz’s law states that the direction of the induced current:

(a) Supports the change causing it
(b) Opposes the change causing it
(c) Is always clockwise
(d) Is always anti-clockwise
Ans: (b) Opposes the change causing it