1.

A transformer is used to light a 140 W, 24 V lamp from 240 V AC mains. The current in mains cable is 0.7 A, find the efficiency of transformer.A. `63.8%`B. `74%`C. `83.3%`D. `48%`

Answer» Correct Answer - C
Output power = 140 W
Input power `= 240xx0.7=168 W`
Efficiency `=("output power")/("input power")xx100=(140)/(168)xx100=83.3%`


Discussion

No Comment Found

Related InterviewSolutions