Level 2

The north pole of a magnet is brought near a metallic ring as shown in fig. The direction of induced current in the ring will be-

Consider the situation shown in the figure. The wire $AB$ is slide on the fixed rails with a constant velocity. If the wire $AB$ is replaced by a semicircular wire; the magnitude of the induced current will

For a coil having $L=2 \mathrm{mH}$, current flows through it is $i=t^2{e}^{-t},$ then the time (in second) at which emf becomes zero is-

A common transistor radio set requires$12 \mathrm{V} (D.C.)$ for its operation. The $D.C.$ source is constructed by using a transformer and a rectifier circuit, which are operated at $220 \mathrm{V} (A\mathit{.}C\mathit{.})$ on standard domestic $A.C.$ supply. The number of turns of secondary coil are $24,$ then the number of turns of primary are

An $LCR$ series circuit is connected to a source of alternating current. At resonance, the applied voltage and the current flowing through the circuit will have a phase difference of-

The flux of magnetic field through a closed conducting loop of resistance $0.4 \mathrm{\Omega }$ changes with time according to the equation $\Phi = 0.20 t^2 + 0.40 t + 0.60$ where $t$ is time in seconds. Find heat produced in $\mathrm{J}$ from $t=0$ to $t=5$ $\mathrm{s}$.

A metal conductor of length $1 \mathrm{m}$ rotates vertically about one of its ends at angular velocity $5$ radians per second. If the horizontal component of earth's magnetic field is $0.2\times {10}^{-4} \mathrm{T}$, then the emf developed between the two ends of the conductor is (in $\mathrm{\mu V}$):

Power factor of an $L-R$ series circuit is $0.6$. and that of a $C-R$ series circuit is $0.5$. If the element ($L, C$ and $R$) of the two circuits are joined in series the power factor of this circuit is found to be $1$. The ratio of the resistance in the $L-R$ circuit to the resistance in the $C-R$ circuit is $\frac{\sqrt{x}}{4}$, find the value of $x$.