ELECTROMAGNETISM TEST 1

Which component is essential in a DC motor but not in an AC motor?

• Stator

• Rotor

• Commutator

• Bearings

Why is the core of a transformer laminated?

• To increase the efficiency

• To reduce the weight

• To reduce eddy current losses

• To increase the magnetic flux

Which device operates on the principle of electromagnetic induction?

• Transformer

• Battery

• Resistor

• Capacitor

What is the unit of the induced electromotive force (EMF)?

• Ohm

• Ampere

• Volt

• Tesla

What determines the voltage transformation ratio in a transformer?

• The type of core material

• The number of turns in the primary and secondary coils

• The frequency of the input current

• The resistance of the windings

Which type of transformer increases voltage from primary to secondary?

• Step-down transformer

• Step-up transformer

• Isolation transformer

• Auto-transformer

What is the shape of the magnetic field lines around a straight current-carrying conductor?

• Circular

• Straight

• Elliptical

• Spiral

What is the unit of magnetic field strength?

• Ampere

• Tesla

• Volt

• Ohm

How can power loss due to resistance in transmission lines be minimized?

• By using thicker conductors

• By increasing the current

• By increasing the voltage

• By using more insulators

How does the velocity of a conductor affect the induced EMF in a magnetic field?

• The induced EMF decreases with increased velocity.

• The induced EMF remains constant.

• The induced EMF increases with increased velocity.

• The induced EMF becomes zero.