An incandescent lamp is marked '120v,75W'
a)what is the current in the lamp under normal condition of operation?
b)How much does it cost per hour to operate the lamp if the price of electrical energy is $6.00 per unit?
Please stop posting under different names.
Use ohms law, remembering Power is I*V
Cost= power*time
a. P = E*I = 75W
120I = 75
I = 0.625A
To answer these questions, we need to use Ohm's Law, which relates voltage, current, and resistance in an electrical circuit.
a) To find the current in the lamp under normal conditions of operation, we can use Ohm's Law formula:
Current (I) = Power (P) / Voltage (V)
The power rating of the lamp is given as 75W, and the voltage is 120V. Substituting these values into the formula:
I = 75W / 120V
Calculating this, we find that the current in the lamp under normal conditions is approximately 0.625 Amperes (A).
b) To calculate the cost per hour of operating the lamp, we need to know the electrical energy consumed by the lamp per hour. We already know the power rating of the lamp (75W), which represents the amount of energy it consumes in one hour.
The cost can be calculated by multiplying the power rating by the cost per unit of electrical energy:
Cost per hour = Power (W) * Cost per unit
In this case, the cost per unit of electrical energy is given as $6.00.
Cost per hour = 75W * $6.00
Calculating this, we find that it costs approximately $450.00 per hour to operate the lamp.