P2 - Resistance and I-V Characteristics (3)

Question 1

What is the constant thing about an Ohmic Conductor

Answer 1

Ohmic Conductors have a constant resistance.

Question 2

What is the rule of current and PD in an Ohmic Conductor

Answer 2

At a constant temperature, the current flowing through an ohmic conductor is directly proportional to the potential difference across it.

Question 3

What is the rule of resistance of a filament lamp?

Answer 3

Resistance increases with temperature, so as the current increases, the filament lamp heats up more and the resistance increases.

Question 4

What is the rule of resistance for a diode?

Answer 4

The resistance depends on the direction of the current. They will let current flow in one direction but have a very high resistance if the current is reversed.

Question 5

What is the I-V Characteristics Practical and Name the Steps.

Answer 5

1)Set up the test circuit for it.
2)Vary the variable resistor. It alter the current flowing through the circuit and the PD across the component.
3)Take several pairs of readings from the am and voltmeters to see how the PD across the component varies as the current increases.
4)Repeat the readings twice more to get an average pd at each current.
5)Swap over the wires connected to the cell, so the direction of the current is reversed.
5)Plot a graph of current against voltage for the component(diode,filament lamp and ohmic conductor)
6)

Question 6

What is the rule of the i-v characteristic for a filament lamp?

Answer 6

As the current increases, the filament lamp temperature increases so the resistance increases.
this means less current can flow per unit PD, so the graph of this gets shallower.