Question 305: Current Electricity

Question

In the given figure, a battery of emf E is connected across a conductor PQ of length 'l' and different area of cross-sections having radii r
1
and r
2
(r
2
< r
1
).
Choose the correct option as one moves from P to Q :

Accepted Answer

Current is constant in conductor
i = constant
Resistance of element $$dR = {{ho dx} \over {\pi {r^2}}}$$
$$dV = idR = {{iho dx} \over {\pi {r^2}}}$$
$$E = {{dV} \over {dx}} = {{iho } \over {\pi {r^2}}}$$
& $${V_d} = {{eE	au } \over m}$$
$$	herefore$$ $${V_d} \propto E$$
$$ 	o E \propto {1 \over {{r^2}}}$$
if r decreases, E will increase : V
d
will increase

Answer

Drift velocity of electron increases.

Answer

Electric field decreases.

Answer

Electron current decreases.

Answer

All of these

Current Electricity

In the given figure, a battery of emf E is connected across a conductor PQ of length 'l' and different area of cross-sections having radii r 1 and r 2 (r 2 < r 1 ). Choose the correct option as one moves from P to Q :

Choose the correct answer: