Is plugged into the outlet of a 120−v circuit that has a 20−a circuit breaker. you plug an electric hair dryer into the same outlet. the hair dryer has power settings of 600 w, 900 w, 1200 w, and 1500 w. you start with the hair dryer on the 600−w setting and increase the power setting until the circuit breaker trips.

Given the point of maximun electric power of the hair dryer 1500 (w); The circuit breaker won´t trip at all

Explanation:

The most simplyfied  relation between power, voltage and current is:

Electric power (in watts) =Voltage (in volts) * current (in ampers)

In the case of P= 1500 (w) and V= 120 (v) we have:

I = 1500/120 (a)    = 12,65 (a)

This value  is far away of 20 (a) (the nominal trip current