A) 2R
B) R/2
C) R/4
D) R/8
Correct Answer: C
Solution :
[c] Resistance of wire (R)\[=\rho \frac{\ell }{A}\] If wire is bent in the middle then \[\ell '=\frac{\ell }{2},A'=2A\] \[\therefore \]New resistance, \[R'=\rho \frac{\ell '}{A'}=\frac{\rho \frac{\ell }{2}}{2A}\] \[=\frac{\rho \ell }{4A}=\frac{R}{4}.\]
You need to login to perform this action.
You will be redirected in
3 sec
