The voltage and the current between $A$ and $B$ points shown in the circuit are $\_\_\_\_$ .

An unpolarized light is incident on the plane interface of air-dielectric medium shown in figure. If the incident angle is equal to Brewster angle, identify the expression representing reflected wave.

A 1 kg block subjected to two simultaneous forces $(2 \hat{\mathrm{i}}+3 \hat{\mathrm{j}}+4 \hat{\mathrm{k}}) \mathrm{N}$ and $(3 \hat{\mathrm{i}}-\hat{\mathrm{j}}-2 \hat{\mathrm{k}}) \mathrm{N}$ is moved a distance of 25 m along $(3 \hat{\mathrm{i}}-4 \hat{\mathrm{j}})$ direction. The work done in this process is $\_\_\_\_$ J.

The surface tension of a soap solution is $3.5 \times 10^{-2} \mathrm{~N} / \mathrm{m}$. The work required to increase the radius of a soap bubble from 1 cm to 2 cm is $\alpha \times 10^{-6} \mathrm{~J}$. The value of $\alpha$ is $\_\_\_\_$ .

$$ (\pi=22 / 7) $$