Topic Menu

Cyber-chess a chess instruction site

Circuits - series and parallel

Q1.

(a) A set of decorative lights consists of a string of lamps. Each lamp is rated at 5.0 V, 0.40 W and is connected in series to a 230 V supply.

Calculate

(i) the number of lamps in the set, so that each lamp operates at the correct rating,

(ii) the current in the circuit,

(iii) the resistance of each lamp,

(iv) the total electrical energy transferred by the set of lights in 2 hours.

(5)

(b) When assembled at the factory, one set of lights inadvertently contains 10 lamps too many. All are connected in series. Assume that the resistance of each lamp is the same as that calculated in part (a) (iii).

(i) Calculate the current in this set of lights when connected to a 230 V supply.

(ii) How would the brightness of each lamp in this set compare with the brightness of each lamp in the correct set?

(3)
(Total 8 marks)