Electricity & Magnetism MCQs with Answers

What is the standard unit of cell potential (electromotive force)?

• A.Volt
• B.Ampere
• C.Ohm
• D.Watt

The transistor is a semiconductor device with at least terminals.

• A.2
• B.3
• C.4
• D.5

How many electrons are present in 1 coulomb of charge?

• A.6.25 × 10¹⁸
• B.1.6 × 10⁻¹⁹
• C.9.1 × 10⁻³¹
• D.6.02 × 10²³

A beam of electrons is provided by _?

• A.Electron gun
• B.Cathode ray tube
• C.X-ray tube
• D.Photoelectric cell

In a transistor, the emitter-base junction is?

• A.Forward biased
• B.Reverse biased
• C.Unbiased
• D.None of these

A coil of 600 turns is threaded by magnetic flux of 8 webers. If this flux is reduced to 5 webers in 3 seconds, the induced EMF in the coil will be _?

• A.1200 V
• B.300 V
• C.900 V
• D.600 V

Brushes used in a generator are commonly made up of _?

• A.Copper
• B.Carbon
• C.Iron
• D.Aluminium

The Superposition Theorem is applicable to ?

• A.Linear networks only
• B.Non-linear networks only
• C.Both linear and non-linear networks
• D.None of these

An electron describes a circular orbit of radius 2 cm in a uniform magnetic field. If the speed of the electron is doubled, then the radius of the orbit will _?

• A.become 8 cm
• B.remain 2 cm
• C.become 1 cm
• D.become 4 cm

The I-V Graph for a non-Ohmic material is always

• A.Straight line passing through origin
• B.Straight line parallel to y-axis
• C.Straight line parallel to x-axis
• D.Curved