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
Critical Thinking
question_answer
The effective resistance between points P and Q of the electrical circuit shown in the figure is [IIT-JEE (Screening) 2002]
A) \[2Rr/(R+r)\]
B) \[8R\,(R+r)/(3R+r)\]
C) \[2r+4R\]
D) \[5R/2\,\,+\,2r\]
Correct Answer:
A
Solution :
In a circuit, any circuit element placed between points at the same potential can be removed, without affecting the rest of the circuit. Here, by symmetry, points A, B and C are at same potential, for any potential difference between P and Q. The circuit can therefore be reduced as shown below Effective resistance \[{{R}_{eq}}=\frac{2Rr}{R+r}\].