Alternating CurrentHard

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 %

Solution

η% = × 100    = × 100 = 83.3%.

Create a free account to view solution

View Solution Free
Topic: Alternating Current·Practice all Alternating Current questions

More Alternating Current Questions

In the series LCR circuit as shown in figure, the voltmeter and ammeter readings are :...Which one of the following has not the same unit...An A.C. circuit containing only capacitance, the current :...Phase difference between V & I at resonance is :...In an L-R series circuit (L = μH and R = 12Ω), a variable emf source (V = V0 sin ωt) of Vrms = 130 &#8730...