Question

A wire has a non-uniform cross-section as shown in figure. A steady current flows through it. The drift speed of electrons at points $P$ and $Q$ is $v_{P}$ and $v_{Q} .$ Then

• A. $v_{P}=v_{Q}$
• B. $v_{P} < v_{Q}$
• C. $v_{P} > v_{Q}$
• D. data insufficient

Answer 1

Answer: (C)

$v_{d}=\frac{i}{A n e} ;$ As $A \uparrow$ so $v_{d} \downarrow \Rightarrow v_{P} > v_{Q}$