Question

If the radius of curvature of a copper wire carrying current is doubled, the drift velocity of the electrons will

• A. remains same
• B. increases four times
• C. decreases four times
• D. increases first and then decreases

Answer 1

The correct option is C decreases four times

Drift velocity of the electrons $v_d=\frac{I}{Ane}$

where $A=\pi r^2$

$⟹$ $v_d\propto \frac{1}{r^2}$ (for same current $I$)

Thus if the radius of curvature of a copper wire carrying current is doubled, the drift velocity of electrons will decrease by four times.