Q. In the circuit shown, the voltage drop across the 15Ω resistor is 30 V having the polarity as indicated. The ratio of potential difference across 5Ω resistor and resistance R is

(a) 2/7

(b) 0.4

(c) 5/7

(d) 1

**Click to See Answer : **

Ans: (d)

Sol: Since , Voltage drop across 15 ohm is 30 V . Hence current in 15 ohm resistor is = 30/15 = 2A

Apply KCL at junction B and find the current in Path BC .

Hence , current in path BC = 2+5 = 7 A

Now , Applying KVL in loop we get

2R = 35 v

Hence , The ratio of potential difference across 5Ω resistor and resistance R is

$ \displaystyle \frac{V_{BC}}{V_R} = \frac{35}{35} = 1 $