10 IGCSE -ELECTRICITY. FOR THE LOVE OF PHYSICS

A plastic rod is rubbed with a dry cloth. The rod becomes positively charged.

Why has the rod become positively charged?

• It has gained electrons.

• It has gained neutrons

• It has lost electrons

• It has lost neutrons.

A circuit contains a cell of electromotive force (e.m.f.) of 2.0 V. The current in the circuit is 2.0 A.

How much energy is converted by the cell in 2.0 minutes?

• 2.0 J

• 4.0 J

• 8.0 J

• 480 J

The circuit diagram shows a cell connected in series to a resistor and a component X.

What is component X?

• bell

• diode

• heater

• thermistor

Identical resistors are connected together to form arrangements X, Y and Z.

What is the correct order of the resistances of the arrangements from the largest to the smallest?

• X → Y → Z

• Y → X → Z

• Z → X → Y

• Z → Y → X

A circuit contains a cell of electromotive force (e.m.f.) 2.0 V, three resistors, three ammeters and two voltmeters. One ammeter is labelled P and one voltmeter is labelled Q.

The readings on the other two ammeters and on the other voltmeter are shown.

What is the reading on ammeter P and what is the reading on voltmeter Q

• A

• B

• C

• D

There is a current of 2.0 A in a resistor for 30 s. The potential difference (p.d.) across the resistor is 12 V.

How much energy is transferred in the resistor?

• 1.25 J

• 5.0 J

• 180 J

• 720 J

Resistors of 1.0 Ω, 2.0 Ω and 3.0 Ω are connected in parallel with a cell.

Which statement is correct?

• The current in each resistor is different but the potential difference (p.d.) across each resistor is the same.

• The current in each resistor is the same but the potential difference across each resistor is different.

• The potential difference across the 3.0 Ω is greater than the potential difference across the 1.0 Ω resistor

• The sum of the potential differences across each resistor is equal to the electromotive force (e.m.f.) of the cell.

The diagram shows a circuit component.

What is it used for?

• to allow current in one direction only

• to change the direction of the current

• to emit light when there is a current

• to increase the size of the current

Where must a fuse be connected in a mains electric circuit?

• the earth wire only

• the live wire only

• the neutral wire only

• the live wire and the earth wire