Electrical Power & Energy Quiz

What is the formula to calculate the power (P) in a circuit if the voltage (V) and current (I) are known?

• \( P = V + I \)

• \( P = \frac{V}{I} \)

• \( P = V \times I \)

• \( P = \frac{V}{I^2} \)

Priya is setting up a small electric heater in her room. If the heater operates at a voltage of 10 volts and draws a current of 2 amperes, what is the power consumption of the heater?

• 5 watts

• 10 watts

• 20 watts

• 40 watts

How do you calculate the energy (E) consumed by a circuit if you know the power (P) and the time (t) the power was used?

• \( E = P + t \)

• \( E = P \times t \)

• \( E = \frac{P}{t} \)

• \( E = P - t \)

Noah's desk lamp uses 50 watts of power. If he studies for 3 hours with the lamp on, how much energy does the lamp consume?

• 150 watt-hours

• 150 joules

• 50 joules

• 50 watt-hours

What unit is commonly used to express electrical energy in the context of household electricity usage?

• Joules

• Kilowatt-hours

• Watts

• Ampere-hours

If a circuit operates at 100 watts for 2 hours, how much energy is used in kilowatt-hours?

• 0.2 kWh

• 2 kWh

• 20 kWh

• 200 kWh

What happens to the power dissipated in a resistor if the voltage across it is doubled, assuming the resistance stays the same?

• It remains the same

• It is halved

• It is doubled

• It is quadrupled

A 60-watt light bulb is used for 10 hours. How much energy does it use in kilowatt-hours?

• 0.6 kWh

• 6 kWh

• 60 kWh

• 600 kWh