2. Electricity Flashcards
1
Q
What would happen when earthed metal sphere brought near to dome and why?
A
See spark
Dome negative, sphere neutral
Electrons repel in dome, some try to travel in air to reach sphere causing spark
2
Q
Why are electric shocks most likely on warm, dry day?
A
Wet day excess electrons repel in water molecules in air
Dry day excess electrons accumulate and can’t travel in air
3
Q
What happens to resistance when current increases?
A
Electrons collide more with ions in wire
Ions vibrate more
Resistance increases
4
Q
How is charge built up on Van de Graaff dome?
A
Motor rotates rubber belt, rubs against motor, gains electrons by friction
Electrons in belt repel each other, disperse into dome as it is conductor so they can spread out
Dome gains electrons, positively charged
