Electrical Quantities (CIE IGCSE Physics: Co-ordinated Sciences (Double Award))

A PVC (plastic) rod is rubbed with a nylon cloth. This process causes electrons to be transferred between the rod and the cloth, causing both objects to become charged.

Which row gives the correct nature of the charges on both the cloth and the rod, and the effect the objects have on each other after becoming charged?

	Charges on rod and cloth	Effect
A	the same	repel
B	the same	attract
C	opposite	repel
D	opposite	attract

A student wants to charge up some rods by rubbing them with a cloth made from a suitable material.

He has a number of rods to choose from: a copper rod, a PVC rod, an aluminium rod and a glass rod.

Which two of the rods would hold a charge when rubbed with an appropriate cloth?

Extended tier only

A student considers how changing the diameter and length of a wire affects its resistance.

Which row shows the changes that could be made to the length and diameter of the wire to decrease its resistance?

	Change to length	Change to diameter
A	increase	increase
B	increase	decrease
C	decrease	increase
D	decrease	decrease

A student rubs an acetate rod with a cloth, giving it a negative charge. She then holds it near an earthed, conducting sphere as shown in the diagrams below.

Which diagram shows the correct distribution of charges on the conducting sphere?

Extended tier only

A student has four copper wires, of different dimensions.

Which of the following wires has the largest resistance?

	Length of wire / cm	Diameter of wire / mm
A	100	0.2
B	300	0.1
C	50	0.4
D	30	0.5

Extended tier only

What is the definition of an electric field?

Extended tier only

Four current-voltage graphs are given below.

Which graph shows an ohmic resistor and which shows a filament lamp?

	Filament lamp	Ohmic resistor
A	Q	S
B	R	Q
C	P	Q
D	Q	R

Extended tier only

Which row in the table gives the correct units for charge and e.m.f.?

	Charge	EMF
A	Q	E
B	C	V
C	A	J
D	J	ᘯ

Extended tier only

A student sets up a circuit as shown in the diagram.

A charge of 4.9 C flows through the resistor in 0.7 s.

Which row shows the correct current, direction of electron flow and direction of conventional current through the resistor?

	current / A	direction of electron flow	direction of conventional current
A	7.00	Left to right	Right to left
B	3.43	Left to right	Right to left
C	7.00	Right to left	Right to left
D	3.43	Right to left	Right to left

A student connects a 6 V power supply to a 3 Ω resistor. The resistor is left connected to the power supply for 1 minute.

How much power is dissipated by the resistor?

A 3.0 Ω resistor is connected to a 15 V power supply as shown in the diagram. The ammeter reads 5 A throughout the experiment.

How much energy is dissipated as heat by the resistor in 2 minutes?

A 2.0 Ω resistor is connected to meter X and meter Y as shown in the diagram.

Which row in the table shows possible values for the two meters?

	X	Y
A	4.0	8.0
B	2.0	2.0
C	4.0	2.0
D	1.0	1.0

A student wants to measure the power dissipated by a 10 kΩ resistor.

What equipment should the student use to determine the power dissipated?