NEETPhysicsCurrent Electricity
Four identical resistors, each of resistance 8 , are connected to form a Wheatstone bridge ABCD . A 15 resistor is connected between the opposite junctions B and D . A battery of EMF 20 V and internal resistance 2 is connected across the other two junctions A and C . The heat energy dissipated in the resistor connected between A and B in 10 s is:
Options
- A125 J
- B80 J
- C320 J
- D500 J
Correct answer
B. 80 J
Step-by-step solution
The four identical resistors form a balanced Wheatstone bridge since the ratio of resistances in the adjacent arms is equal ( 8 8 = 8 8 ). Therefore, no current flows through the 15 resistor connected between B and D , and it can be ignored for further calculations. The equivalent resistance of the bridge across A and C is the parallel combination of branch ABC ( 8 + 8 = 16 ) and branch ADC ( 8 + 8 = 16 ): R_ eq = 16 16 16 + 16 = 8 . The total resistance of the circuit includes the internal resistance of the batter