Question

In a wire of circular cross-section with radius r, free electrons travel with a drift velocity v, when a current i flows through the wire. What is the current in another wire of half the radius and of the some material when the drift velocity is 2v

• A. 2i
• B. I
• C. *i/*2
• D. *i/*4

Answer 1

Answer: (C)

*i/*2

Answer 2

$i = n e A v _ { d }$= neπr²v and