Second Year Physics Chapter 15 Online MCQ Test for 2nd Year Physics Chapter 15 Electromagnetic Induction Preparation

Lenz's law deals with

• Magnitude of emf A
• Direction emf B
• Direction of induced current C
• Resistance D

In A.C. generator , when plane of coil is perpendicular to magnetic field, then output of generator is.

• NwAB A
• 2pi f B
• Maximum C
• Zero D

If we make magnetic field stronger the value of induced current is.

• Decreased A
• Increased B
• Vanishes C
• Remain constant D

Electromagnetic induction obeys law of conservation

• Charge A
• Energy B
• Momentum C
• Mass D

• Lenz's law A
• Faraday's law B
• Ampere's law C
• None of these D

The winding of the electromagnet in motor are usually called.

• Magnetic coils A
• Field coils B
• Electric coils C
• electric o electric coils D

When back emf in motor is zero, it draws.

• Zero current A
• Minimum current B
• Maximum current C
• Steady current D

Induced emf in A.C. generator can be increased by

• Decreasing area of coil A
• Decreasing magnetic field B
• Increasing area of coil C
• Slowing down speed of coil D

A step up transformer is used 120 V line to provide 240 V. If primary coil has 100 turns the number of turns is secondary is.

• 50 A
• 100 B
• 150 C
• 200 D

When motor is just started, back emf is almost.

• Maximum A
• Zero B
• Minimum C
• Infinite D

DC generator by william Sturgeon in:

• 1894 A
• 1961 B
• 1834 C
• 1961 D

Lenz's law was given by Heinrich lenz in:

• 1894 A
• 1904 B
• 1854 C
• 1834 D

Energy stored in an inductor is:

• 1/2L²I A
• 1/2L²/I B
• _1/2LI² C
• 1/2LI D

In D.C. generator, split rings act as.

• Capacitor A
• Commutator B
• Resistor C
• Inductor D

B2/2p is the expression of.

• Lenz's law A
• Magnetic energy B
• Magnetic energy density C
• Back emf D

EMF is induced due to change in

• Charge A
• Current B
• Magnetic flux C
• Electric field D

When a motor is over loaded then the magnitude of back emf.

• Increases A
• Decreases B
• Remain constant C
• Zero D