Question

The maximum allowed rms current in a circuit before its circuit breaker trips is 12.5 A . If a maximum emf of 180 V is connected to a device whose resistance is 8.4 ohms, will the circuit breaker trip and interrupt the flow of electricity

Answer 1

The circuit will break .

Explanation:

The potential difference of 180 V is applied across resistance = 8.4 ohm

Thus the maximum current flowing I₀ = $\frac{V}{R}$ = $\frac{180}{8.4}$ = 21.4 A

The rms value of the current is = $\frac{I_0}{\sqrt{2} }$  =  I₀ x 0.7 = 15 A

This value of current is greater than the 12.5 A . Thus the circuit will break .