-
The value of the resistance R in the circuit shown in the given figure is varied in such a manner that the power dissipated in 5 Ω resistor is maximum. Under this condition, the value of R will be—
-
- 20 Ω
-
40 Ω 3 - Ω
- 30 Ω
Correct Option: B
Power draw through the 5 Ω (i.e. load resistance) will be maximum if and only if Rth = RL calculation for Rth for the given circuit. 
| Rth = | 8 + R |
| = 5 | 8 + R |
8R = 5R + 40
3R = 40
| R = | Ω | 3 |
