The AC voltage across a resistance can be measured using a: (a) potentiometer (b) moving coil galvanometer (c) moving magnet galvanometer (d) hot wire voltmeter

Answer: (d). A hot wire instrument works on heating effect, H ∝ I², which does not depend on current direction. Potentiometer and moving coil / moving magnet galvanometers respond to the average (dc) value, which is zero for ac. So the answer is (d) hot wire voltmeter.

The AC voltage across a resistance can be measured using a: | JEE Main 2015 (11 Apr, Shift 1)

Q41JEE Main 2015 · 11 APR · SHIFT 1Easy

AC Basics: Peak, RMS & Average Values

The AC voltage across a resistance can be measured using a:

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Answer: (d)

A hot wire instrument works on heating effect, $H \propto I^2$ , which does not depend on current direction.
Potentiometer and moving coil / moving magnet galvanometers respond to the average (dc) value, which is zero for ac.
So the answer is (d) hot wire voltmeter.

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