Question

A 20.00-ohm, 5.00-watt resistor is placed in series with a power supply.(a) What is the maximum voltage that can be applied to the resistor without harmingthe resistor?(b) What would be the current through the resistor?

Answer 1

Answer:

(a) 10.00V

(b) 0.5V

Explanation:

(a) The power(P) supplied by a resistor of resistance (R) when a voltage(V) is passed across is given by;

P = V² / R       ------------------(i)

From the question;

P = 5.00W

R = 20.00Ω

Substitute these values into equation (i) as follows;

5.00 = V² / 20.00

V² = 5.00 x 20.00

V² = 100.00

V = $\sqrt{100.00}$

Solve for V;

V = 10.00V

Therefore, the maximum voltage that can be applied without harming the resistor is 10.00V

(b) By Ohm's law the current (I) flowing through a resistor of resistance (R) when a voltage (V) is applied is given by;

V = I x R

=> I = V / R             ----------------(ii)

Substitute the values of V and R into equation (ii) as follows;

I = 10.00 / 20.00

I = 0.5A

Therefore, the current through the resistor is 0.5A