Calculation of power consumption of a 200W-200V lamp connected to 250V mains

First, we need to determine the current flowing through the lamp using Ohm's Law:

I = V/R

Where I is the current, V is the voltage, and R is the resistance of the lamp. Since the lamp is rated at 200V and 200W, we can use the formula:

R = V^2/P

Where R is the resistance of the lamp, V is the voltage, and P is the power rating of the lamp. Substituting the given values, we get:

R = (200)^2/200 = 200Ω

Now, we can calculate the current flowing through the lamp:

I = 250/200 = 1.25A

Therefore, the power consumption of the lamp can be calculated using the formula:

P = VI

Substituting the values, we get:

P = 250 x 1.25 = 312.5W

Explanation of the calculation

The calculation is based on the principle of Ohm's Law, which states that the current through a conductor between two points is directly proportional to the voltage across the two points, and inversely proportional to the resistance between them.

In this case, since the lamp is rated at 200V and 200W, we can determine the resistance of the lamp using the formula R = V^2/P. Substituting the given values, we get R = (200)^2/200 = 200Ω.

Once we have determined the resistance, we can calculate the current flowing through the lamp using the formula I = V/R. Substituting the given values, we get I = 250/200 = 1.25A.

Finally, we can calculate the power consumption of the lamp using the formula P = VI. Substituting the values, we get P = 250 x 1.25 = 312.5W. This means that the lamp is consuming 312.5W of power from the mains supply.