Question

The power rating of a 400-Ω resistor is 0.300 w. (a) What is the maximum voltage that can be applied across this resistor without damaging it? (b) What is the maximum current this resistor can draw without damaging it?

Answer 1

Answer:

(A) 10.95 volts (B) 0.0273 A

Explanation:

We have given resistance R =400 ohm

The power rating of the resistor is P =0.300 W

(A) We know that power across the resistor is given by $P=\frac{V^2}{R}$ here V is voltage and R is resistance

So $0.3=\frac{V^2}{400}$

$V^2=120$

$V=10.95\ volts$

(B) The power across a resistor is also given by $P=i^2R$

$0.3=i^2\times 400$

$i^2=7.5\times 106{-4}$

$i=0.0273A$