Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर
JEE Main & Advanced
Physics
Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर
Question Bank
Electric Conduction, Ohm's and Resistance
question_answer
An electric wire of length ?I? and area of cross-section \[a\] has a resistance R ohms. Another wire of the same material having same length and area of cross-section 4a has a resistance of [MP PMT 1993]
A) 4R
B) R/4
C) R/16
D) 16R
Correct Answer:
B
Solution :
\[R=\frac{\rho l}{a}\] for first wire and R?=\[\frac{\rho l}{4a}=\frac{R}{4}\]for second wire.