Question

I need to drop 10 V to feed an LED from a 12 V power supply. The resistor value is 490 Ω. How much of my battery power will be wasted in the resistor?

Answer 1

Answer:

P = 0.204 W

Explanation:

Given that,

Voltage drop is 10 V to feed an LED from a 12 V power supply. The resistor value is 490 Ω.

We need to find how much of my battery power will be wasted in the resistor. The power of a battery is given in terms of voltage and resistance is given by :

$P=\dfrac{V^2}{R}$

V is the voltage drop to feed an LED

Putting all the values,

$P=\dfrac{(10)^2}{490}\\\\P=0.204\ W$

So, 0.204 W of power will be wasted in the resistor.