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When a certain a.c supply is connected to a lamp, it lights with the same bright...


Question

When a certain a.c supply is connected to a lamp, it lights with the same brightness as it does with a 12 V d.c battery. Then r.m.s value of the a.c supply is?

Options

A) 12.0 V

B) 3.5 V

C) 17.0 V

D) 8.5


The correct answer is A.

Explanation:

The r.m.s value of an a.c voltage/current is the value of the d.c. voltage/ current that will dissipate the same amount of energy in a given resistance as the a.c. Thus the r.m.s value of the a.c supply is 12v.

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Dicussion (1)

  • The r.m.s value of an a.c voltage/current is the value of the d.c. voltage/ current that will dissipate the same amount of energy in a given resistance as the a.c. Thus the r.m.s value of the a.c supply is 12v.

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