For the circuits shown in figures $I$ and $II$,the voltmeter reading would be

As the temperature of the hot junction of a thermocouple is increased (while the cold junction is at a constant temperature), the thermo $e.m.f.$

For the circuit shown in the figure:
$(A)$ The current $I$ through the battery is $7.5 \text{ mA}$.
$(B)$ The potential difference across $R_L$ is $18 \text{ V}$.
$(C)$ The ratio of powers dissipated in $R_1$ and $R_2$ is $3$.
$(D)$ If $R_1$ and $R_2$ are interchanged,the magnitude of the power dissipated in $R_L$ will decrease by a factor of $9$.

Assertion : An electric bulb becomes dim,when the electric heater in parallel circuit is switched on.
Reason : Dimness decreases after sometime.

When a current of $1\, A$ is passed through a conductor whose ends are maintained at a temperature difference of $1\, ^oC$,the amount of heat evolved or absorbed is called:

For a thermocouple,the temperature of inversion is that temperature at which the thermo $e.m.f.$ is: