Homework Practice

Printable assignment

Electric Current and Its Effects: Practice 2

Processes and Observations

Question 1mcq

Why is replacing a fuse wire with a thick copper wire unsafe?

A.Copper wire makes the circuit waterproof.

B.Thick copper always reduces voltage to zero.

C.The thick wire may not melt during excess current, so protection is lost.

D.The appliance becomes lighter.

Question 2mcq

An MCB trips repeatedly when a heater and iron run together. What is the best first response?

A.Tape the MCB in the ON position.

B.Replace the MCB with a nail.

C.Pour water on the switchboard.

D.Switch off some appliances and check for overload.

Question 3mcq

What happens when electric current flows through a wire near a compass?

A.The compass needle may deflect.

B.The compass needle disappears.

C.The wire turns into plastic.

D.The cell becomes a flower.

Question 4mcq

Which observation shows the magnetic effect of current?

A.A dry seed absorbs water.

B.A compass needle moves when placed near a current-carrying wire.

C.Ice melts in sunlight.

D.Salt dissolves in water.

Question 5mcq

If current in a coil is switched off, what usually happens to its magnetic effect?

A.It becomes permanent in every material.

B.It doubles forever.

C.It disappears or becomes very weak.

D.It turns into heat only in all cases.

Reasoning Practice

Question 6mcq

How can the strength of a simple electromagnet generally be increased?

A.Remove the iron core and cut the wire.

B.Use a dry wooden core only.

C.Open the switch permanently.

D.Increase the number of turns of wire around the iron core.

Question 7mcq

Why is soft iron commonly used as the core of an electromagnet?

A.It becomes magnetised easily and loses magnetism when current stops.

B.It is always an electrical insulator.

C.It melts at room temperature.

D.It cannot be affected by current.

Question 8mcq

Which device commonly uses an electromagnet?

A.Wooden ruler

B.Electric crane for lifting scrap iron

C.Plain glass tumbler

D.Cotton cloth

Question 9mcq

In an electric bell, what pulls the iron strip towards it when current flows?

A.Dry cell label

B.Wooden base

C.Electromagnet

D.Glass cover

Question 10mcq

Why does the hammer in an electric bell vibrate repeatedly?

A.The gong becomes a battery.

B.The switch stays open forever.

C.The hammer is heated until it melts.

D.The circuit keeps making and breaking as the strip moves.