Three `10 Omega , 2 W` resistors are connected as in Fig. `7.34`. The maximum possible voltage between points `A and B` without exceeding the power dissipation limits of any of the resistors is

Options

A. `5 sqrt(3) V`
B. `3 sqrt(5) V`
C. `15 V`
D. ` (5)/(3) V`

Answer

B

Explanation

Power `= (V^(2))/( R )`
or `V = sqrt(PR) = sqrt(2 xx 10) = sqrt(20) = 2sqrt(5) V`
Clearly, voltage across single resistor of `10 Omega` cannnot exceed `2 sqrt(5) V`. Note that the resistance of parallel combination is half of `10 Omega` . Thus, the maximum possible voltage between `A and B` is `3 sqrt(5) V`.