Search SchoolNGR

Tuesday, 03 March 2026
Register . Login

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

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?
Take Free Practice Test On 2026 JAMB UTME, Post UTME, WAEC SSCE, GCE, NECO SSCE
  • A 12.0 V
  • B 3.5 V
  • C 17.0 V
  • D 8.5
Correct Answer: Option 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.

Share question on: