(1) A current(I) flow through a uniform wire of diameter (d) when the mean drift velocity is V.The same current will flow through a wire of diameter d/2 made of the same material ,Then the maen drift velocity of the electron is
(a) V/4 (b) V/2
(c) 4V (d) 2V
(ans:-) (c)
(2) (Q) A wire of non-uniform cross-section is carrying a steady current. Along the wire
(a) current and current density are constant
(b) only current is constant
(c) only current density is constant
(d) neither current nor current density is constant
(ans:-)(b)
(3) When a potential difference (V) is applied across a conductor , the thermal speed of electrons is
(a) zero
(b) proportional to √T
(c) Proportional to (T)
(d) proportional to (V)
(ans:-) (b)
(4) A metallic block has no potential difference applied across it. then the mean velocity of free electron is
(a) Proportional to T
(b) proportional to √T
(c) Zero
(D) Finite but independent of temperature.
(ans:-) (c)
(5) A steady current is passing through a linear conductor of non-uniform cross-section .The current density in the conductor is
(a) independent of area of cross-section
(b) directly proportional to the area of cross-section
(c) inversly proportional to the area of cross-section
(d) inversly proportional to the square root of area of cross-section.