Electric Bills Science

The kilowatt-hour is the unit of

• electrical charge

• electrical energy

• electrical power

• voltage

1. 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-PS3-1

It costs $0.30 for 1 kWh of electrical energy.

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

• $0.05

• $0.18

• $3.00

• $18.00

Tags

NGSS.HS-PS3-1

An electric heater is rated 230V, 10A. Which fuse is most suitable for the electric heater?

• 10A

• 15A

• 30A

• 13A

A microwave oven rated 1.2kW, 240V is connected to a 240V electricity supply. Calculate the current that flows through the oven.

• 5A

• 0.05A

• 200A

• 0.2A

Tags

NGSS.HS-PS2-4

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

Tags

NGSS.HS-PS3-1