Alternating CurrentMedium
Question
A transformer is used to light a 140 watt, 24 volt lamp from 240 V AC mains. The current in the main cable is 0.7 amp. The efficiency of the transformer is :
Options
A.48 %
B.63.8 %
C.83.8 %
D.90 %
× 100 = 
× 100 = 83.3%. More Alternating Current Questions
Choke coil works on the principle of :-...A series R-C circuit is connected to AC voltage source. Consider two cases; (A) when C is without a dielectric medium an...The electric current in the circuit is given as $i = i_{o}(t/T)$. The r.m.s current for the period $t = 0$ to $t = T$ is...A 100 V, 50 Hz A.C. supply is connected to a series L-R circuit. The current in the circuit is 5A and the average power ...For the series LCR circuit connected with 220 V , 50 Hz a.c source as shown in the figure, the power factor is $\frac{\a...