DC ciruits (II) & practical electricity

Question 1

light dependent resistor LDR trend

Answer 1

R ⬇️ when light ⬆️

bright light, low R
dim light, high R

Question 2

electric power

Answer 2

rate of energy conversion

S.I unit: W

Question 3

power rating

Answer 3

indicates the amount of power the resistor can safely dissipate without being destroyed

Question 4

30W, 240V bulb

(i) when connected to 240V

Answer 4

(i) bulb will light up but appear dinner because power developed in the lamp is reduced
power is lower than the power rating of the bulb

(ii) bulb may blow (or fuse) because the power developed in the lamp is larger than 30W
power in the bulb is higher than the power rating of the bulb

Question 5

thermistor trend

Answer 5

R ⬇️ when temp ⬆️