Question

An alternating voltage V = 140 sin 50t (in Volts) is applied to a resistor of resistance 10$\Omega$. This voltage produces $△$H heat in the resistor in time interval $△$t. To produce the same amount of heat in the same time interval, required DC current is approximately equal to:

• A. 14 A
• B. 20 A
• C. 10 A
• D. none of these

Answer 1

The correct option is C 10 A

V = 140 sin 50t
Current $i=\frac{140}{10}sin50t{i}_m=14AD.Ccurrent=rmscurrent=\frac{i_m}{\sqrt{2}}=\frac{14}{\sqrt{2}}=10A$ approximately.