Lecture 5

Question 1

E =

Answer 1

Electric field strength =

V / l

Voltage / length

Question 2

R (condusctivity equa) =

Answer 2

Resistance =

l / (σ A)

length / conductivity X area

Question 3

Resistivity and conductivity relationship

Answer 3

resistivity = 1 / conductivity

Question 4

R (resistivity equa) =

Answer 4

resistance =

(ρ l) / A

resistivity X length / area

Question 5

Increasing the temperature of a metal causes the metal atoms to

Answer 5

vibrate with more amplitude so they are further from their equilibrium positions

Question 6

At a low temperture, a metals conductivity is ——- as the metal atoms are moving —–, so the electrons do not ——- with the metal ions

Answer 6

higher, less, collide

Question 7

At a high temperture, a metals conductivity is ——- as the metal atoms are moving —–, so the electrons ——- with the metal ions

Answer 7

lower, more, collide

Question 8

At a high temperture, a metals conductivity is ——- as the metal atoms are moving —–, so the electrons ——- with the metal ions

Answer 8

lower, more, collide

Question 9

ρT =

Answer 9

resistivity at temperature =

ρr ( 1 + α ( T - Tr ) )

resistivity at a reference temperature ( 1 + temperature resistivity coefficient ( temperature - reference temperature) )

Question 10

Conduction in a material is by the movement of

Answer 10

electrons and “holes”

Question 11

Increasing temperature in a semi-conductor material:
- releases more ——
- creating more ——
- increases the ——– – ——- —–
- conductivity ———

Answer 11

electrons, holes, number of charge carriers, increases

Question 12

Semi conductor materials without impurities are referred to as

Answer 12

intrinsic