A transformer supplies 12V when connected to a 240V mains. If the transformer takes 0.120A from the mains when used to light a 12V, 24W lamp, what is its efficiency?
A
57.20%
B
66.60%
C
83.30%
D
92.50%
E
100%
Verified Correct Answer: C.
Physical Principles & Numerical Solution
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #42902)