Electrical Resistance Exercise, .

[claudiadeluca]

Please help with the following exercise:

How much should the electrical resistance of a light bulb be in order to consume a power of 60W if a voltage of 220V is applied?

This is how I solved it:

Power= Voltage^2 / Resistance

60W = 220V^2 / R

R = 807 ohms

Is it correct? Thank you.

 

[Astronuc]

Yes - the answer is correct.

for DC, Power = Voltage * Current, or P = V*I, but I = V/R, so

P = V²/R.

In this application, V is the potential difference driving the current I through resistance R.

When solving problems, it is best to write out the applicable equations so as to check one's understanding of the physics.

 

[m2003]

Yes, your calculation is correct. According to Ohm's law, the resistance (R) of a device is equal to the voltage (V) squared divided by the power (P) consumed by the device. In this case, the power (60W) and voltage (220V) are known, so solving for resistance gives us 807 ohms. However, it's important to note that this calculation assumes the light bulb is operating at its rated power and voltage. If the voltage or power fluctuates, the resistance may change as well.