1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# A transformer is used to light a 120W, 24V lamp from 240V a.c. mains. The current in the main cable is 0.6A. The efficiency of the transformer is

A
48%
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
63.8%
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
83.3%
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
90%
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

## The correct option is C 83.3%Answer is C.The efficiency of a transformer can be calculated using Equation,Efficiency=OutputpowerofthetransformerInputpowerofthetransformer=PsPp×100In this case, the output power is 120W.The input power is calculated as follows.The input voltage is 220 V and current is 5 APower=VI=240×0.6=144W.So, η=120144×100=83.3.Hence, the efficiency of the transformer that lights the bulb is 83.3%.

Suggest Corrections
0
Join BYJU'S Learning Program
Related Videos
Transformer
PHYSICS
Watch in App
Explore more
Join BYJU'S Learning Program