Electricity - Power calculations

Calculate the power generated as a 20 A current flows through a 10Ω resistor?

• 2 W

• 200 W

• 4000 W

• 400 W

How much power can be generated from a 20A current flow because of a 1 kV battery?

• 20 W

• 20000 W

• 0.05 W

• 0.5 W

What is the resistance of a 75 W bulb with 5 A of current flowing through it?

• 3 Ω

• 15 Ω

• 375 Ω

• Resistance is futile!

What is the power of a 20V bulb with 5A through it?

• 100W
• 100V
• 6.3W
• 6.3A

What is the resistance through a 700 mV bulb with a power of 1 kW?

• 7 Ω

• 4.9 x 10^-4 Ω

• 7 x 10^-4Ω

• 70 Ω

Calculate the current through a microwave oven that has a power rating of 800W and a potential difference of 230V.

Give your answer to 3 significant figures.

calculate the power of a kettle that has a potential difference of 230 V and a current 10 A.

Don't include commas or spaces in your answer

the equation that links power (P), current (I) and potential difference (V) is...

• P=I/V

• V=IP

• I=VP

• P=IV

the unit of power is the...

• Watt

• Joule

• Ohm

• Newton

power is defined as...

• the strength of the current

• the rate of energy transfer

• energy transferred per Coulomb of charge

• the ratio of potential difference across a component to the current through it.