resistivity & resistance

Question 1

Define resistivity

Answer 1

to define how strong a given material opposes the flow of electrical current

Question 2

What does a low resistivity show?

Answer 2

that a material readily allows the flow of electric current

Question 3

What does a high resistivity show?

Answer 3

that a material opposes the flow of electrical current

Question 4

What is the SI unit for resistivity?

Answer 4

ohm meter

Question 5

What would happen if the tempreature changed?

Answer 5

As the tempreature rises, so would the resistance (execpt carbon)

Question 6

What are the four laws of the resistance conductor?

Answer 6

• length
• area
• resistivity
• tempreature

Question 7

Law 1 (length) - what would happen to the resistance, if the material had a long length?

Answer 7

• the resistance would have doubled depending on the proportions in length
• example: 1ohm turns into 2ohms

Question 8

Law 2 (area) - what would happen to the resistance if the material thickens?

Answer 8

-the resistance would be halved
- example: 2ohms would turn to 1ohm

Question 9

Law 3 (resistivity) - why is it important what material to use?

Answer 9

• the resistivity of a material also depends upon what it is made of, its atomic structure, and the number of electrons within the structure

Question 10

Law 4 (temperature) - what would happen if the temperature rises?

Answer 10

• the resistance of conductors increases as the temperature increases (except carbon)

Question 11

How do we calculate resistance if laws 1 and 2 were to be used?

Answer 11

Resistance = Length/Cross-sectional Area

Question 12

How do we calculate resistance if all three laws were to be used?

Answer 12

Resistance = Resistivity x Length/Cross-sectional Area

Question 13

What do we also use the second formula for?

Answer 13

To calculate the resistance for a specific length for a conductor