An electric lamp has 100 W written on it; 120 V. Determine what the current

| June 25, 2021 | education

An electric lamp has 100 W written on it; 120 V. Determine what the current and resistance will be if you connect it to the network with the voltage for which it is designed.

The inscriptions on the lamp bulb mean that if it is connected to a network with a voltage of U = 120 (V), then it will consume power P = 100 (W).

In order to determine the strength of the current that will pass along the spiral of the lamp, we use the formula for the power of the electric current:

P = U * I,

where I is the current strength.

We express I from this formula and make the appropriate calculations:

I = P / U = 100/120 ≈ 0.833 (A).

To determine the resistance (R) of the lamp spiral, it uses Ohm’s law for a homogeneous circuit:

I = U / R,

from where

R = U / I,

substitute the values ​​of U and I, we get:

R = U / I = 120 / 0.833 = 100 (Ohm),

Answer: I ≈ 0.833 (A), R = 100 (Ohm).



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