Ch:18 Electrical quantities

What is an electric current in a metal wire?

• A a flow of electrons

• B a flow of neutrons

• C a flow of nucleons

• D a flow of protons

Four wires are made of the same metal. Which wire has the greatest resistance?

• A a 100 cm long wire with a diameter of 3.0 mm

• B a 100 cm long wire with a diameter of 6.0 mm

• C a 10 cm long wire with a diameter of 3.0 mm

• D a 10 cm long wire with a diameter of 6.0 mm

A student uses four ammeters P, Q, R and S to measure the current in different parts of the circuit shown. Which two ammeters read the largest current?

• A P and Q

• B P and R

• C R and Q

• D R and S

A circuit X is set up with two identical lamps. Circuit Y is then set up, changing the positions of the meters. On which meters do the readings change?

• A both the ammeter and the voltmeter

• B the ammeter only

• C the voltmeter only

• D neither the ammeter nor the voltmeter

The circuit shown includes a battery, three lamps X, Y and Z and three switches S1, S2 and S3.Lamp X is off but lamps Y and Z are lit. Which switches are closed?

• A S1 and S2 only

• B S1 and S3 only

• C S2 and S3 only

• D S1, S2 and S3

A student uses the circuit shown to determine the resistance of two identical resistors. The voltmeter reading is 2.2V and the ammeter reading is 0.25A. What is the resistance of each resistor?

• A 0.275Ω

• B 0.55Ω

• C 4.4Ω

• D 8.8Ω

The circuit shown contains five lamps J, K, L, M and N. All the lamps are glowing.One lamp is removed and two other lamps go out. Which lamp is removed?

• A lamp J

• B lamp K

• C lamp L

• D lamp M

Three electrical quantities are listed.

● potential difference ● electromotive force ● current Which quantities are measured in volts?

• A potential difference only

• B potential difference and current only

• C potential difference and electromotive force only

• D potential difference, electromotive force and current

Lamps in a circuit are connected in parallel. What is the advantage of this?

• A If one lamp breaks, the others remain lit.

• B Less current is taken from the power supply.

• C The lamps use less power than if they were connected in series.

• D The potential difference across each lamp is less than that of the power supply.

The diagram shows a reading on an ammeter. What is the reading?

• A 0.45A

• B 0.50A

• C 4.5A

• D 5.0A