Data Entry - Physics

$A$ cell of $emf$ $E$ and internal resistance $r$ is connected in series with an external resistance $nr$. Then,the ratio of the terminal potential difference to $emf$ is

The solution of $x \frac{dy}{dx} = y + x e^{y/x}$ with $y(1) = 0$ is

More than $70\%$ of the world's freshwater is contained in:

$A$ conducting rod of length $2l$ is rotating with constant angular speed $\omega$ about its perpendicular bisector. $A$ uniform magnetic field $\vec B$ exists parallel to the axis of rotation. The $e.m.f.$ induced between the two ends of the rod is

Which of the following statements is correct for any thermodynamic system?