Question

1.A 2000 W toaster operates on a household circuit of 200 V. What is the resistance of the wire the make up the heating element of the toaster?

2.An electronic device is rated at 0.35 W when connected to 150 V. What is the resistance of this device?

Answer 1

P - power measured in watts
E - voltage measured in volts
I - current measured in amperes
R - resistance measured in ohms


`E=IR \\P=IE`

1. P = 2000 W, E = 200 V, R = ?


`P=IE \\2000=I200 \\I=10 \\E=IR \\200=10R \\R=20`

2. P = 0.35 W, E = 150 V, R = ?


`P=IE \\0.35=I150 \\I= (0.35)/(150) \\ E=IR \\150=(0.35)/(150)R \\R= (150^2)/(0.35) \\R= 64285.71`