Electricity & Magnetism MCQs with Answers

A wire of uniform cross-section A, length L and resistance R is cut into two equal pieces. The resistivity of each will be?

• A.The same
• B.Double
• C.Half
• D.One-fourth

Magnetic influence of current was discovered by _?

• A.André-Marie Ampère
• B.Hans Christian Oersted
• C.Michael Faraday
• D.James Clerk Maxwell

Which of the following is considered an example of an insulator?

• A.Copper
• B.Silver
• C.Wood
• D.Iron

If the turns ratio of a transformer is 5, the secondary voltage is greater than the primary voltage by factor _?

• A.0.2
• B.10
• C.25
• D.5

The needle in the compass is always directed toward _?

• A.West
• B.South
• C.East
• D.North

Capacitance of a parallel plate capacitor in the presence of insulator having dielectric constant εr is C. If the dielectric is removed from plates, then new capacitance will be

• A.C (unchanged)
• B.C × εr
• C.C + εr
• D.C / εr

The resistance of a conductor depends on?

• A.Length of the conductor
• B.Cross-sectional area of the conductor
• C.Temperature and nature of material
• D.All of these

The magnitude of the current in metals is proportional to the potential difference across it as long as the temperature of the conductor is kept constant. This is known as?

• A.Ohm's Law
• B.Faraday's Law
• C.Joule's Law
• D.Coulomb's Law

The S.I. unit of Electric flux is _?

• A.Volt per meter (V/m)
• B.Newton per coulomb (N/C)
• C.Newton meter² per coulomb (N·m²/C)
• D.Coulomb per meter² (C/m²)

A capacitor is a device used to store _?

• A.Electric current
• B.Electric charge
• C.Electric power
• D.Magnetic field