Rubbing an insulating rod with a cloth transfers ______ from its surface, leaving the rod with an overall positive charge.

In the cradle method for demonstrating electrostatic charge, how is the test material suspended?

In the cradle method, what result shows that two charged rods carry the same type of charge?

In the cradle method, what result shows that two charged rods carry opposite types of charge?

True or False? In the cradle method, if the suspended rod is attracted to the second charged rod, the two rods must carry the same type of charge.

Define an electric field.

Define a uniform electric field.

In which direction do electric field lines point around an isolated point charge?

What does the direction of a field line at a given point represent?

Field lines drawn close together show a ______ electric field, while field lines drawn far apart show a ______ electric field.

Describe the electric field lines between two oppositely charged parallel plates.

Why are the field lines around a charged conducting sphere symmetrical, just like those around a point charge?

True or False? As the distance between two charged objects decreases, the electrostatic force between them becomes weaker.

Define electric charge.

Electric charge is measured in units called ______.

What type of force acts between two objects that carry the same type of charge?

What type of force acts between two objects that carry opposite types of charge?

True or False? Two objects that are both negatively charged will attract each other when brought close together.

Define current.

Charge, current and time are related by the equation: charge = current × ______.

How is current measured, and how must the meter be connected in a circuit?

Define conventional current.

True or False? In a metal, current is caused by a flow of free (delocalised) electrons.

What is the difference between direct current (d.c.) and alternating current (a.c.)?

What type of current do cells (batteries) produce, and what type does mains electricity supply?

Define electromotive force (e.m.f.).

Define potential difference (p.d.).

How does the energy transfer described by e.m.f. differ from that described by potential difference?

How should a voltmeter be connected to measure the potential difference across a component?

Voltmeters can be either ______ (with a needle and scale) or digital (with an electronic read-out).

True or False? When several cells are connected in series, their combined e.m.f. is equal to the sum of their individual e.m.f.s.

In a series circuit, how does the sum of the potential differences across the components compare with the e.m.f. of the power supply?

Define an electrical conductor.

Define an electrical insulator.

Why do metals conduct electricity well, in terms of their atomic structure?

What piece of apparatus can be used to test whether a material is a conductor or an insulator?

Describe the main parts of a gold-leaf electroscope.

In a gold-leaf electroscope test, what result shows that the tested material is a good conductor?

If the gold leaf falls ______ when a material touches the charged plate, that material is a poor conductor.

True or False? If the gold leaf remains sticking out when a material touches the charged plate of the electroscope, that material is a good conductor.

Define resistance.

State Ohm's law in words.

Write the equation linking resistance, potential difference and current, in symbol form.

For a given potential difference, the ______ the resistance, the lower the current.

True or False? According to Ohm's law, the potential difference across a conductor decreases as its resistance increases, for a constant current.

Describe the circuit set-up used to determine the resistance of a component.

A charge of 5.0 C passes through a resistor at a constant rate in 3.0 s. The potential difference across the resistor is 2.0 V. Calculate the resistance.

How does the resistance of a wire vary with its length?

How does the resistance of a wire vary with its cross-sectional area?

Define ohmic conductor.

Why does the current in a filament lamp increase at a slower rate than the potential difference as the p.d. across it is increased?

Define thermistor.

True or False? As the temperature of a thermistor increases, its resistance increases.

Thermistors are used in temperature-sensing circuits such as ovens, fire alarms and digital ______.

In a circuit where a thermistor is connected in series with a fixed resistor R, what happens to the potential difference across the thermistor when its temperature decreases?