JEE Main 2026 · 4 Apr · Shift 1 · Physics Q37

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PhysicsSingle correct+4 / -1Question 37 of 75

A voltmeter with internal resistance of $x$ Ω can be used to measure upto 20 V. In order to increase its measuring range to 30 V, the required modification is to ________.

connect resistor of

\dfrac x2

Ω, in series with voltmeter.

connect resistor of

\dfrac x2

Ω, in parallel to voltmeter.

connect a resistor of

x

Ω in series with voltmeter.

connect resistor of

2x

Ω in parallel to voltmeter.

Answer and worked solution

Official answer: A

Series resistor. Full-scale current $\frac{20}x$ must give 30 V across $x+R$ :
$\frac{20}x(x+R)=30\implies R=\frac x2.$

(A)

Topics:Ammeters and voltmeters

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JEE Main 2026 · 4 Apr · Shift 1, Physics question 37