Mock Questions

Question 1

Explain in terms of particle behaviour why the resistance of the nichrome wire changes as temperature increases

Answer 1

Kinetic energy energy of ions increases

Frequency of collisions between electron + ions

Drift velocity of electrons decrease so current decreases

So resistance of nichrome wire increases

Question 2

Describe why a plank on top of a rock will tip if she walks from one side to the other

Answer 2

Plank will topple when clockwise moment is greater than anticlockwise moment

(Show using numerical values x > y)

Question 3

Bulbs are connected in parallel, another bulb is added
Explain why the bulbs will get dimmer and temperature of bulbs increase as more bulbs are added (6marks)

Answer 3

The resistance of circuit decreases as more bulbs are added so current increases
Therefore voltage increases
Terminal pd decreases and bulb gets dimmer
More energy transferred in battery
So thermal energy increases