Current Electricity - Result Question 23
24. A, B and C are voltmeters of resistance $R, 1.5 R$ and $3 R$ respectively as shown in the figure. When some potential difference is applied between $X$ and $Y$, the voltmeter readings $are V_A$, $V_B$ and $V_C$ respectively. Then
[2015]
(a) $V_A \neq V_B=V_C$
(b) $V_A=V_B \neq V_C$
(c) $V_A \neq V_B \neq V_C$
(d) $V_A=V_B=V_C$
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Answer:
Correct Answer: 24. (d)
Solution:
- (d) Effective resistance of $B$ and $C$
$=\frac{R_B \cdot R_C}{R_B+R_C}=\frac{1.5 R \times 3 R}{1.5 R+3 R}=\frac{4.5 R^{2}}{4.5 R}=R$
i.e., equal to resistance of voltmeter $A$.
In parallel potential difference is same so, $V_B=V_C$ and in series current is same So, $V_A=V_B=V_C$
