Electricity & Magnetism MCQs with Answers

An insulator has?

• A.Overlapping valence and conduction bands
• B.Partially filled valence band
• C.Empty valence band
• D.Completely filled valence band

A square coil of side 16 cm has 200 turns and rotates in a uniform magnetic field of magnitude 0.05 T. If the peak emf is 12 V, what is the angular velocity of the coil?

• A.70.5 rad s⁻¹
• B.94 rad s⁻¹
• C.23.5 rad s⁻¹
• D.47 rad s⁻¹

An inductor coil may appear like a _?

• A.Capacitor
• B.Resistor
• C.Solenoid
• D.Transformer

In an induction motor connected in parallel, load can be shifted through ?

• A.Field Rheostat
• B.Starter
• C.Slip Ring
• D.Commutator

In an AC generator the emf will be maximum when factor sinωt is equal to ?

• A.0
• B.1
• C.0.5
• D.−1

A residual-current device (RCD) is widely used in electrical circuits for which purpose?

• A.For shock safety
• B.For voltage regulation
• C.For increasing current flow
• D.For reducing power consumption

If the current in an electric bulb decreases by 0.5%, then the power in the bulb decreases by approximately ?

• A.0.5%
• B.1%
• C.2%
• D.0.25%

The SI unit of current is the ampere and represented by capital letter 'A'. One Ampere is equal to ?

• A.Coulomb/Second
• B.Joule/Second
• C.Volt/Ohm
• D.Watt/Volt

The unit of magnetic flux density is ?

• A.Weber (Wb)
• B.Henry (H)
• C.Tesla metre (Tm)
• D.Wbm⁻²

What is the formula for electric power?

• A.P = V²I
• B.P = V/I
• C.P = I/V
• D.P = VI