Assertion $(A):$ In a meter bridge experiment, null point for an unknown resistance is put inside an enclosure maintained at a higher temperature. The null point can be obtained at the same $p$ as before by decreasing the value of the standard resistance.

Reason $(R):$ Resistance of metal increases with increase in temperature.

The resistance per centimeter of a meter bridge wire is $\mathrm{r}$, with $\mathrm{X}\  \Omega$ resistance in left gap. Balancing length from left end is at $40 \mathrm{~cm}$ with $25\  \Omega$ resistance in right gap. Now the wire is replaced by another wire of $2 \mathrm{r}$ resistance per centimeter. The new balancing length for same settings will be at

A meter bridge set up as shown to determine end correction at $A$ and $B$. When a resistance of $15\ \Omega$ is used in left gap and of $20\ \Omega$ in right gap, then null point comes at a distance $42\ cm$ from $A$. When these resistances are interchanged null point comes at a distance $57\ cm$ from $A$. Values of end corrections are

In the circuit shown, a meter bridge is in its balanced state. The meter bridge wire has a resistance $0.1\, ohm/cm$. The value of unknown resistance $X$ and the current drawn from the battery of negligible resistance is

A resistance of $2 \Omega$ is comnected across one gap of a metre-bridge (the length of the wire is $100 \mathrm{~cm}$ ) and an unknown resistance, greater than $2 \Omega$, is connected across the other gap. When these resistance are interchanged, the balance point shifts by $20 \mathrm{~cm}$. Neglecting any corrections, the unknown resistance is