How does current affect resistance in different components?

Question 1

Describe the graph of a fixed resistor.

Answer 1

1. The voltage is directly proportional to the current.
2. The graph has a constant gradient b/c the resistance of the fixed resistor stays the same.
3. Looks like the graph of y=x

Question 2

Describe the graph of a filament lamp.

Answer 2

1. The voltage is not directly proportional to the current.

2. The graph looks like a cliff.

Question 3

Why does the resistance of a filament lamp increase?

Answer 3

As p.d increases so does the temperature of the wire inside the bulb. This increases the vibrations of the electrons in the filament, which increases the overall resistance of the bulb, as it is harder for the electrons in the circuit to go through.

Question 4

Describe the graph of an LDR and its properties.

Answer 4

1. voltage is not directly proportional to the current.
2. Very high resistance in darkness.
3. Very low resistance in brightness.
4. Looks like a downward curve.

Question 5

Describe the graph of an LED.

Answer 5

1. Resistance increases as the p.d. increases.
2. Non-ohmic component.
3. Looks like an upward curve.

Question 6

Describe the graph of a thermistor.

Answer 6

1. Resistance increases as the p.d. increases.
2. Very high resistance in cold conditions.
3. Very low resistance in hot conditions.
4. Looks like a downward curve.