Physics Flashcards

A current-carrying conductor is placed in a magnetic field. The force on the conductor is zero when the angle between the current direction and magnetic field is:

Answer: 0°

The force on a conductor F = BIL sinθ is zero when θ = 0° or 180° (current parallel to field), but θ = 0° is the standard answer.

In an AC circuit, the phase difference between voltage and current in a pure capacitor is:

Answer: Current leads voltage by 90°

In a pure capacitive circuit, the current leads the applied voltage by 90° (π/2 radians).

The SI unit of magnetic flux is:

Answer: Weber (Wb)

Magnetic flux Φ = B·A is measured in Weber (Wb), where 1 Wb = 1 T·m².

A transformer has 500 primary turns and 50 secondary turns. If the primary voltage is 220 V, the secondary voltage is:

Answer: 22 V

Using V₂/V₁ = N₂/N₁: V₂ = 220 × (50/500) = 22 V.

The electric field inside a charged hollow spherical conductor is:

Answer: Zero

By Gauss's law, the electric field inside a hollow charged conductor is zero because no charge resides inside.

Two capacitors of capacitance C each are connected in series. The equivalent capacitance is:

Answer: C/2

For capacitors in series: 1/C_eq = 1/C + 1/C = 2/C, so C_eq = C/2.

The phenomenon of electromagnetic induction was discovered by:

Answer: Michael Faraday

Michael Faraday discovered electromagnetic induction in 1831, showing that a changing magnetic flux induces an EMF.