Electric Usage

The kilowatt-hour is the unit of

• electrical charge

• electrical energy

• electrical power

• voltage

What is the formula to calculate electrical power?

• potential difference / current

• potential difference / resistance

• potential difference x current

• potential difference x resistance

An electric heater takes 4A of current from a 250V supply when operating normally.
How long would it take the heater to convert 400 000 J of electrical energy?

• 40 s

• 400 s

• 1000 s

• 1600 s

Tags

NGSS.HS-PS3-3

How much will it cost to run a 60 W lamp for 10 hours?

• $0.05

• $0.18

• $3.00

• $18.00

A family of four lives in a three-bedroom house and uses an average of 900 kWh of electricity per month. The family cools their house for 3 months with 2 window units that each use 350 kWh of electricity per month. Which of the following is the percentage of the family’s total annual electricity that is used to run the two air conditioners for the three summer months?

• 9.7

• 19.4

• 38.8

• 77.8

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-4

Which of the following best describes energy transformation in a battery-powered flashlight?

• Chemical to Electrical to Light

• Mechanical to Electrical to Light

• Solar to Chemical to Light

• Thermal to Electrical to Light

energy produced by the flow of electrons (electricity)

• sound

• energy

• electrical

• thermal

Tags

NGSS.MS-PS2-3

NGSS.MS-PS3-5

An electric rice cooker rated 800W, 230V is switched on for 30 minutes. How much electrical energy is used?

• 400kWh

• 3.48kWh

• 0.4kWh

• 104kWh

Tags

NGSS.HS-PS3-1

An electric rice cooker rated 800W, 230V is switched on for 30 minutes. Calculate the cost of energy that is used by the rice cooker if the cost per kWh is 30sen.

• RM12

• RM0.12

• RM1.20

• RM120

current is measured in....

• volts

• amps

• watts

• mph