NEET Practice Questions (MCQs) with Answers & Solutions

Displacement current is :

A circular ring of radius r is placed in a homogeneous magnetic field perpendicular to the plane of the ring. The field B changes with time according to the equation B = Kt, where K is a constant and t is the time. The electric field in the ring is

A cycle wheel of radius 0.5 m is rotated with a constant angular velocity of 10 rad/s in a region of a magnetic field of 0.1 T which is perpendicular to the plane of the wheel. The EMF generated between its centre and the rim is:

If the current in an AC circuit is given as $\mathrm{i}=\left(5\mathrm{A}\right)\sin \left(\mathrm{\omega t}-\frac{\mathrm{\pi }}{3}\right)$ when an emf $\mathrm{e}=\left(200\mathrm{V}\right)\mathrm{sin\omega t}$ is applied across the circuit. The circuit having component only

A step-down transformer is employed to reduce the main supply of AC from 220V to 11V. If the primary coil draws a current of 5A and the secondary supplies a current of 90A, then the efficiency of the transformer is  -

At resonance, the value of the power factor of the circuit is -

In a LCR circuit having L = 8.0 henry, C = 0.5 $\mathrm{\mu F}$ and R = 100 $\mathrm{\Omega }$ in series, the resonance frequency (in Hz) is 

In a LCR series network, ${\mathrm{V}}_{\mathrm{L}}=40 \mathrm{V}, {\mathrm{V}}_{\mathrm{C}}=20 \mathrm{V} \mathrm{and} {\mathrm{V}}_{\mathrm{R}}=15 \mathrm{V}$. The supply voltage is

The ratio of the number of turns in secondary to primary in an ideal transformer varies from 50 to 550. If the power input is P, then its output power is  -

Loss in energy in the transformer is due to