Electricity & Magnetism MCQs with Answers

Like charges always ?

• A.Repel each other
• B.Attract each other
• C.Remain stationary
• D.None of these

Which one of the following statements is not correct regarding electric and magnetic fields?

• A.Electric field lines originate from positive charges and terminate on negative charges.
• B.Magnetic field lines always form closed loops.
• C.When current passes through a straight wire, magnetic field lines are also produced in straight line.
• D.A changing magnetic field can produce an electric field.

Electrical energy is converted into chemical energy by _?

• A.Electrolytic cell
• B.Galvanic cell
• C.Solar cell
• D.Electric motor

The flow of charge through a uniform cross section wire in a unit time is called ?

• A.Current
• B.Voltage
• C.Resistance
• D.Power

No-load test on the DC motor is known as ?

• A.Hopkinson's Test
• B.Swinburne's Test
• C.Brake Test
• D.Retardation Test

When resistances are connected in series, the current passing through them is _?

• A.Different
• B.Same
• C.Zero
• D.Infinite

The operation used in rectification is?

• A.Conversion of low voltage to high voltage
• B.Conversion of DC to AC
• C.Conversion of AC to DC
• D.Conversion of high voltage to low voltage

The resistance of a semiconductor with rise in temperature ?

• A.Increases
• B.Decreases
• C.Remains the same
• D.First increases then decreases

The turn ratio of a transformer is 10. It means ?

• A.Ip = 10 Is
• B.Np = 10 Ns
• C.Vs = 10 Vp
• D.Ns = 10 Np

Why are shields made of iron usually provided around precision instruments?

• A.For protection against mechanical shocks and vibrations
• B.For protection against dust and moisture
• C.For protection against the effect of external magnetic fields
• D.For protection against temperature fluctuations