P4

Question 1

Current through component measured with?

Answer 1

Ammeter. Always placed in series with the component. Unit of current is the Amp.

Question 2

Pd across component measured with?

Answer 2

Voltmeter. Placed parallel with component. Pd unit is Volt.

Question 3

Ohm’s law states?

Answer 3

Current through a resistor at constant temperature is directly proportional to pd across resistor. (Ohmic conductor obeys this).

Question 4

Resistance unit?

Answer 4

Ohms

Question 5

Filament bulb?

Answer 5

Resistance increases with increase of the filament temperature.

Question 6

Diode?

Answer 6

Forward resistance low reverse distance high.

Question 7

Thermistor?

Answer 7

Resistance decreases if temperature increases.

Question 8

Ldr?

Answer 8

Resistance decreases if light intensity on it increases.

Question 9

In a series circuit?

Answer 9

Components connected one after the other, a break in circuit = charge stops flowing.
Current same in each component as no choice of route for charge as it flows.
Adding pd gives total pd.
Adding resistance gives total resistance.

Question 10

In a parallel circuit?

Answer 10

Each component connected across a supply, one break in one part, charge still flow in other parts.
Total current= sum of currents through the separate components.
Bigger resistance of component smaller current is.
Pd same in each component.

Question 11

When two electrically insulated materials rub together?

Answer 11

Electrons rubbed off one material and deposited on the other. Electrons negative charge so material which gained electrons becomes negatively charged. Ones lost becomes positively charged.= charging by friction.