Solutions of Electricity (Page No- 48) - Physics By Lakhmir Singh, Class 10 | Extra Documents, Videos & Tests for Class 10 PDF Download

Lakhmir Singh Physics Class 10 Solutions Page No:48

Question 10:
If you were going to connect two light bulbs to one battery, would you use a series or a parallel arrangement ? Why ? Which arrangement takes more current from the battery ?
Solution :
Parallel arrangement because if one electrical bulb stops glowing due to some defect the other will keep glowing.
Parallel arrangement takes more current from the battery due to its lesser equivalent resistance.

Question 11:
(a) Which is the better way to connect lights and other electrical appliances in domestic wiring : series circuits or parallel circuits ? Why ?
 (b) Christmas tree lamps are usually wired in series. What happens if one lamp breaks ?
 (c) An electrician has wired a house in such a way that if a lamp gets fused in one room of the house, all the lamps in other rooms of the house stop working. What is the defect in the wiring ?
 (d) Draw a circuit diagram showing two electric lamps connected in parallel together with a cell and a switch that works both lamps. Mark an   on your diagram to show where an ammeter should be placed to measure the current.

Solution :
(a) Parallel circuits – Because if one electrical appliance stops working due to some defect, then all other appliances in the circuit will keep working properly.
(b) All the other lamps stop glowing.
(c) All lamps are connected in series.
(d)

Question 14:
(a) Draw a circuit diagram showing two lamps, one cell and a switch connected in series.
 (b) How can you change the brightness of the lamps ?
Solution :

(a) 

(b) The brightness of the lamps can be changed by connecting the lamps in parallel.

Question 15:
Consider the circuit given below where A, B and C are three identical light bulbs of constant resistance.

(a) List the bulbs in order of increasing brightness.
 (b) If C burns out, what will be the brightness of A now compared with before ?
 (c) If B burns out instead, what will be the brightness of A and C compared with before ?
Solution :
(a) C will be the brightest. Voltage will be distributed equally between A and B, so they will have equal brightness but lesser than that of C.
(b) A gets the same voltage as before, so its brightness remains the same.
(c) If B burns put, A will also stop glowing because it is connected in series with B. However, brightness of C remains the same.

Question 16:
How do you think the brightness of two lamps arranged in parallel compares with the brightness of two lamps arranged in series (both arrangements having one cell) ?
Solution :
The brightness of two lamps arranged in parallel is much more those arranged in series.

Question 17:
If current flows through two lamps arranged :
 (a) in series,
 (b) in parallel,
 and the filament of one lamps breaks, what happens to the other lamp ? Explain your answer.
Solution :
(a) In case of series connection, if filament of one lamp breaks, the other wil stop glowing.
(b) In case of parallel connection, if filament of one lamp breaks, the other will keep glowing.