Electromagnetic Induction and Alternating Currents — MCQ Practice

A coil of 100 turns and area $5\,\text{cm}^2$ is placed in a magnetic field of $0.2\,\text{T}$ with its plane perpendicular to the field. If the magnetic field is uniformly reduced to zero in $0.1\,\text{s}$, the magnitude of the induced EMF is:

A $20\,\text{mH}$ inductor, a $50\,\Omega$ resistor, and a $200\,\mu\text{F}$ capacitor are connected in series to an AC source. At what angular frequency will the circuit be in resonance?

A step-up transformer has a turn ratio of $1:10$. If the primary voltage is $220\,\text{V}$ and the primary current is $5\,\text{A}$, what are the secondary voltage and current, assuming an ideal transformer?

Which of the following statements about Lenz's Law is INCORRECT?

An AC source is connected across a pure inductor of inductance $L$. If the instantaneous voltage across the inductor is $V = V_0 \sin(\omega t)$, what is the instantaneous current through the inductor?

A metal ring is held above a large electromagnet. When the current in the electromagnet is suddenly switched ON, the ring will: