M3 Sci Finals 1st Sem

Which of the following is not a source of electrical energy?

A. Solar cell

B. Transformer

C. Dynamo

D. Dry cell

The voltage across a load resistor is the…

A. rate of electrical charges that flows across the resistor

B. electrical energy supplied to each charge to move across the resistor

C. resistance against the current that flows through the load resistor

D. measure of electrical power across the load resistor

An electric current in a circuit involves the movement of…

A. atoms

B. molecules

C. electrons

D. particles

The unit for measuring resistance is…

A. volt

B. ampere

C. ohm

D. wat

Which of the following are the advantages of a parallel circuit?
I   Every component in the circuit can be switched on and off separately.
II  Appliances that require different amounts of current can be used at the same time.
III If one of the components is faulty, the other components will be affected.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

The kilowatt-hour (kWh) is a unit for…

A. voltage

B. current

C. power

D. energy

A 50 W immersion heater is used to heat up water in a container for 20 minutes. How much electrical energy has been converted into heat energy?

A. 1000 J

B. 20000 J

C. 40000 J

D. 60000 J

1.5 kW electric kettle is used for 2 hours. How long will it take a 60 W lamp to use the same amount of electrical energy?

A. 20 hours

B. 50 hours

C. 100 hours

D. 200 hours

If the cost of 1 kWh of electricity is 2.5 Baht, what is the cost of using a 2 kW air conditioner for 8 hours?

A. 24 Baht

B. 36 Baht

C. 40 Baht

D. 48 Baht

Which of the following is not a safety device in the wiring system at home?

A. Fuse

B. Earth wire

C. Circuit breaker

D. A 3-pin plug