☰
✕

Electric Charges and Fields
Question
Wired Faculty App

A transforner is used to light a 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 A, the efficiency of the transformer is approximately:



  • 30%

  • 50 %

  • 90 %

  • 10 %

Answer

C.

90 %

The efficiencvy of transformer
 
Energy obtained from the secondary coil
__________________________________
Energy given to the primary coil
n = output
     _______
     Input
Given VsIs = 100 W, Vp = 220 V, IP = 0.5 A
Hence, n = 100 / 220 x 0.5 = 90 %

Sponsor Area

Some More Questions From Electric Charges and Fields Chapter

a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not?
b) Explain why two field lines never cross each other at any point?