3 Resistivity 3 test questions

A wire of uniform diameter 0.28mm and a length of 1.50m has a resistance of 45Ω. It's resistivity is

• 2.2 x 10^-8Ωm

• 36 Ωm

• 1.8 x 10^-6Ωm

• 3.4 x 10^-7Ωm

• A

• B

• C

• D

Which statement about superconductors is correct?

• When a material becomes a superconductor, its resistivity is almost zero.

• The temperature at which a material's resistance falls to ZERO is called the critical temperature.

• When

  current passes through a superconductor the pd across it becomes a maximum.

• Copper is a superconductor at room temperature

Which is an application of thermistors?

• Fire sensor

• Motion sensor

• Automatic night lamps

What happens to the resistance of a light-dependent sensor as light levels increase?

• It increases

• It stays the same

• It decreases

• It fluctuates