2nd Year Physics Chapter 15 Online MCQ Test for 12th Class Physics Chapter 15 (Electromagnetic Induction)

A real transformer does not change.

• Voltage level A
• Current level B
• Power level C
• Frequency D

Efficiency of transformer does not affected by

• Input voltage A
• Core of transformer B
• Insulation between sheet C
• Resistance of coils D

The direction of induced current is always so as to oppose the change which causes the current is:

• Faraday's law A
• Lenz's  law B
• Ohm's law C
• Kirchhoff's 1st rule D

Energy density of an inductor is:

• UM=1/2μ_∘/B² A
• Um = 2μ_∘/B B
• UM = 1/2B²/μ_∘ C
• Um = 2B²/μ_∘ D

A 50 mH coil carries a current of 2.0 a , then energy stored in tis magnetic field is.

• 0.1 J A
• 10 J B
• 100 J C
• 1000 J D

Step up transformer is used.

• Step up D.C. voltage A
• Step up A.C. voltage B
• Step up both A.C and D.C. C
• Step up A.C. current D

split rings are used in

• A.C. generator A
• A.C. motor B
• Transformer C
• D.C. motor D

The only difference between the construction of D.C and A.C is.

• Carbon burshes A
• Coil B
• Commutator C
• Magnetic field D

A current generator device converts:

• Mechanical energy into chemical energy A
• Chemical energy into electrical energy B
• Mechanical energy into electrical energy C
• Both b and c D

Electromagnetic induction obeys law of conservation

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

Commutator was invented in

• 1834 A
• 1820 B
• 1840 C
• 1835 D

The induction can be increased by winding the wire around a core made of.

• Copper A
• Silicon B
• Iron C
• Aluminum D

Output of D.C. motor is

• A.C. energy A
• Mechanical energy B
• Chemical energy C
• D.C. energy D

A metal rod of 1 m is moving at a speed of 1 ms-1 in a direction making an angle 30 ^o with 0.5 T magnetic field . The emf produced is.

• 0.25 N A
• 2.5 N B
• 0.25 V C
• 2.5 V D

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

the core of transformer is laminated so reduce.

• Magnetic loss A
• Hysteresis loss B
• Eddy current loss C
• Electric loss D

If the coil is wound on iron core, the flux through it.

• Decreases A
• Becomes zero B
• Increases C
• Remains constant D