Question

When a metal conductor connected to the left gap of a meter bridge is heated, the balancing point,

• A. Shifts towards right
• B. Shifts towards left
• C. Remains unchanged
• D. Remains zero

Answer 1

The correct option is A Shifts towards right

When the metal conductor $\text{A}$ connected to the left gap is heated then its resistance will increase $(\because R\propto T)$.

Now from the balanced bridge condition,

$\frac{R_A}{R_B}=\frac{l_1}{l_2}=\frac{l_1}{100-l_1}.......\left(1\right)$

$(l_1$ being the distance of null point on meter bridge wire from left end $)$


From equation $\left(1\right)$, if $R_A\uparrow$ then $l_1\uparrow$.

Thus, the balance point or null point will shift towards right.