electricity

Question 1

How do light or temperature affect resistance in an LDR/thermistor?

Answer 1

As light/temperature increases, resistance decreases?

Question 2

What is a diode?

Answer 2

A device that allows current to flow one way but not the other.

Question 3

Define current

Answer 3

The flow of electrical charge

Question 4

What is the equation for total charge through a circuit?

Answer 4

Q = IT
Q = total charge
I = current in amps
T = time in seconds

Question 5

What is the equation linking potential difference, current and resistance?

Answer 5

V = IR
V = potential difference in volts
I = current in amps
R = resistance in ohms

Question 6

What is the difference between an ohmic and a non-ohmic conductor?

Answer 6

Ohmic has a constant resistance
Non-ohmic has changing resistance

Question 7

Draw the practical that can be used to find a component’s I-V characteristics.

Answer 7

google it idk i’m not paying for premium

Question 8

Draw the I-V characteristic graphs for an ohmic conductor, a filament lamp, and a diode. Explain why each one has its shape.

Answer 8

Ohmic - Because the current through an ohmic conductor at a constant temperature is directly proportional to potential difference.

Filament lamp - As the current increases, the temperature of the filament increases, increasing the resistance, causing the graph to get shallower.

Diode - Current only flows through a diode in one direction - it has a very high resistance in the reverse direction.

Question 9

How are potential difference, current and resistance managed in a series circuit?

Answer 9

• The potential difference of the supply is shared between the components.
• The same current flows through all components.
• Resistance adds up.

Question 10

State the potential difference of the live wire, the neutral wire, and the earth wire.

Answer 10

230V , 0V , 0V.

Question 11

What is the difference between alternating current and direct current, and what are they used for?

Answer 11

In ac, the current is constantly changing direction. The UK mains supply is an ac of 230V.
In dc, the current always flows in the same direction. It is used in cells and batteries.

Question 12

a) What is the equation linking energy transferred, power and time?
b) An appliance transfers 6000 J of energy in 30 seconds. Calculate its power.

Answer 12

Energy transferred = power x time

J/T = 6000/30 = 200 W.

Question 13

What is the equation linking energy transferred (J), charge flow (C), and PD (v)?
b) A motor is attached to a 3V battery. 140C of charge passes through it. Calculate the energy transferred.

Answer 13

Energy Transferred (J) = Charge Flow (Q,C) x PD (V)
E = QV

Q x V = 140 x 3 = 420 J.

Question 14

What is the difference between a series and a parallel circuit?

Answer 14

A parallel circuit has branches, a series does not.