P3.2 knowlege gaps

Question 1

energy and charge and p.d relationship

Answer 1

energy= charge x p.d

Question 2

power energy and time relationship

Answer 2

energy = power x time

Question 3

why does resistance of some components change

Answer 3

metal is made of positively charged ions
ions are formed when electrons leave outer shell of metal atoms
the delocalised electrons are free to move through the metal
when colliding resistance is produced

Question 4

why when there are two resistors in parallel the net resistance is decreased?

Answer 4

when adding another lamp the total current increases and the net current decreases

Question 5

how does thermistor resistance change with temperature

Answer 5

considering a certain pd:

at LOW temperatures there is a LOW current therefore à HIGH resistance

at HIGHER temperatures there is a HIGHER current therefore à LOWER resistance of the thermistor

Question 6

how the resistance of an LDR changes with light intensity

Answer 6

as light intensity INCREASES more electrons are released and the resistance decreases