Current Equation

Question 1

Charge Carrier Density

Answer 1

The number of mobile charge carriers per cubic metre

Question 2

What’s the charge carrier density of a metal?

Answer 2

Large- making them good conductors

Question 3

What’s the resistivity of a metal?

Answer 3

Very low

Question 4

What’s the charge carrier density of a semi-conductor?

Answer 4

Low

Question 5

What’s the resistivity of a semi-conductor?

Answer 5

High

Question 6

What happens in metals when the temperature increases?

Answer 6

Mean drift velocity decreases due to increased lattice vibrations- increases resistivity

Question 7

What’s the charge carrier density of an insulator?

Answer 7

Very low

Question 8

What’s the resistivity of an insulator?

Answer 8

Huge

Question 9

What happens in NTC’s as temperature increases?

Answer 9

Number of charge carriers increases, reducing resistivity
Increased lattice vibrations too, but this increase in resistivity is small compared to the number of charge carriers released

Question 10

What happens in an LDR when there’s more light?

Answer 10

More charge carriers are released using the energy transferred, increasing the charge carrier density- lower resistivity