Question

The voltmeter shown in the figure reads 18V across 50Ω resistance. Then resistance of the voltmeter is –

• A. 50 Ω
• B. 90 Ω
• C. 130Ω
• D. None of these

Answer 1

Answer: (C)

130Ω

Answer 2

18 = $\frac{30x}{30 + x}$ ⇒ x = 36 ∴ 36 = $\frac{R.50}{R + 50}$

⇒ R ≈ 130 Ω