Chapter 9.4 - Resistance

Question 1

Resistance definition

Answer 1

Ratio of potential difference across compinent against current in component

R = V/I

Question 2

Ohm definition

Answer 2

Resistance of component when pd of 1V is produced per ampere

1 Ω = 1 V/A

Question 3

Ohm’s law definition

Answer 3

• Metallic conductor kept at constant temperature

* Current in wire is directly proportional to pd across its ends

Question 4

Describe the relationship of temperature and resistance

Answer 4

• As current increases, wire gets hotter
• As wire gets hotter, resistance increases
• As resistance increases, current decreases

Question 5

Describe the effect of temperature of a wire in terms of particles

Answer 5

• As temperature increases, positive ions vibrate with greater amplitude around mean positions

• Frequency of collisions between electrons and ions increase
-electrons transfer more energy through wire