Q. In figure, when an ideal voltmeter is connected across 4000Ω resistance, it reads 30V. If the voltmeter is connected across 3000Ω resistance, it will read
(a) 20V
(b) 22.5V
(c) 35V
(d) 40V
Click to See Answer :
Ans: (b)
Sol: Let I be the current in the circuit .
I × 4000 = 30
I = 30/4000 A
Reading across 3000 ohm = I ×3000
$ \displaystyle = \frac{30}{4000}\times 3000 $
= 22.5 V