1.10 Resistance and Resistivity

Question 1

What happens to current and voltage in a series circuit?

Answer 1

In a series circuit, current stays the same but voltage splits up.

Question 2

What happens to current when being split in a parallel circuit?

Answer 2

The current in each branch is inversely proportional to the resistance of the branch.

Question 3

What happens to current and voltage in a parallel circuit?

Answer 3

In a parallel circuit, current splits up but voltage stays the same.

Question 4

What happens to resistance in a series circuit?

Answer 4

The total resistance in series is the summation of individual resistances.

Question 5

What is resistivity?

Answer 5

The resistance of 1m of material of cross-sectional area of 1m squared.

Question 6

What is the definition of a super conductor?

Answer 6

A material which loses all of its resistivity to become a perfect conductor when it is below its critical temperature.

Question 7

What is another name for critical temperature?

Answer 7

Transition temperature.

Question 8

What is the definition of critical temperature?

Answer 8

The temperature at which a material loses its electrical resistivity and becomes a super conductor.

Question 9

What are the applications of super conductors?

Answer 9

1. Production of powerful electromagnets (with no generation of heat)
   MRI scanners - extremely strong magnetic fields produced.
   Maglev (magnetic levitation) - extremely strong magnetic fields produced.
2. Transmission of electrical power - power loses greatly reduced to zero resistance.

Question 10

What is Ohm’s Law?

Answer 10

The potential difference across conductor is proportional to current through it, provided temperature remains constant.

Question 11

What is a diode?

Answer 11

A diode is an electrical device allowing current to move through in one direction with far greater ease than in the other direction.

Question 12

What is the most common type of diode?

Answer 12

Semi-conductor diode.

Question 13

What are the applications of diodes?

Answer 13

• Protecting component
• Rectifying a voltage
• Controlling signal sizes

Question 14

What does ntc stand for?

Answer 14

Negative temperature coefficient

Question 15

What is an ntc thermistor?

Answer 15

Thermistors are temperature-sensing elements, their resistance depends on temperature.

Question 16

What are the applications of ntc thermistors?

Answer 16

• Temperature measurement (thermostats)
• Temperature compensation
• Temperature control