# Current, Potential Difference and Resistance Questions

1. If a lamp is measured to have a resistance of 45 ohm when it operates at a power of 80 W, what is the current in the lamp?

A. 2.10 A

B. 1.3 A

C. 0.91 A

D. 0.83 A

2. If a lamp has a resistance of 120 ohm when it operates at a power of 1.00 x 10^2 W, what is the potential difference across the lamp?

a. 110 V

b. 120 V

c. 130 V

d. 220 V

3. An electric toaster requires 1100 W at 110 V. What is the resistance of the heating coil?

a. 7.5 ohm

b. 9.0 ohm

c. 1.0 x 10^1 ohm

d. 11 ohm

Please show the work done, formulas used and the answer. Thank you!

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#### Solution Preview

I = Current, R = Resistance, V = Voltage, P = Power

Ohm's Law = V = I*R

...

#### Solution Summary

Ohm's Law = V = I*R

P = V*I = I^2*R = V^2/R

I = Current, R = Resistance, V = Voltage, P = Power

$2.19