Assuming the cost of energy from the electric company is $0.135/kWh, compute the cost per day of operating a lamp that draws a current of 1.45 A from a 110-V line

Cost per day of operating lamp is $0.517.

Explanation:

Power consumed by the electric lamp is given by the relation:

P = I x V

Here I is current and V is the voltage of the lamp.

Substitute 1.45 A for I and 110 volts for V in the above equation.

P = 1.45 x 110 = 159.5 W

We know that 1 kW = 1000 W

So, we convert the power into kW;

P = = 159.5 x 10⁻³ kW

Energy consumed by the electric lamp is given by the relation :

E = P x t

Here t is time.

Substitute 159.5 x 10⁻³ kW for P and 24 h for t in the above equation.

E =  159.5 x 10⁻³ x 24 = 3.828 kWh

Cost of energy from the electric company for 1 kWh = $0.135

Cost of energy operating a lamp per day = $ ( 0.135 x 3.828 )

                                                                     = $ 0.517