Question

In the circuit shown in the figure, reading of voltmeter is V₁ when only S₁ is closed, reading of voltmeter is V₂ when only S₂ is closed and reading of voltmeter is V₃ when both S₁ and S₂ are closed. Then –

• A. V₃> V₂> V₁
• B. V₂> V₁> V₃
• C. V₃> V₁> V₂
• D. V₁> V₂> V₃

Answer 1

Answer: (B)

V₂> V₁> V₃

Answer 2

When only S₁ is closed, i = $\frac{E}{R + 3R}$ = $\frac{3}{4R}$

Reading V₁ = (3R) = $\frac{3E}{4}$ = 0.75 E

When only S₂ is closed i = $\frac{E}{7R}$

Reading V₂ = i(6 R) = $\frac{6E}{7}$= 0.86 E

When S₁and S₂ both are closed, R_eq = R + 2R = 3R

i =$\frac{E}{3R}$, V₃ = i(2R) = $\frac{2E}{3}$ = 0.67 E, V₂ > V₁ > V₃