1Write the difference between a natural magnet and an artificial magnet.
2Write the difference between a plug and a socket.
3Write the difference between the live wire and the neutral wire.
4Give the reason: magnetism is destroyed when a magnet is hammered.
5Give the reason: the value of dip at a magnetic pole is 90°.
6Give the reason: wires of different colours are used in household electrification.
7Give the reason: in a household electric circuit the fuse is always fitted on the phase or live wire.
8In what conditions does magnetic property weaken? Explain any one of them.
9Describe the molecular theory of magnetism with a figure.
10Write the uses of magnets.
11What is the earth's magnetism?
12Mention the effects of the earth's magnetism.
13What is household electricity? Write the features of the phase wire and the neutral wire used in a household electric circuit.
14'It is the effect of the earth's magnetism that has produced magnetism in various magnetic objects.' Make this statement clear with an example.
15Mention the way wires are connected in a plug.
16What is earthing? Why is it necessary in a household electric circuit?
17'The arrangement of the molecular magnets decides whether an object is magnetic or non magnetic.' According to this statement, is the magnetic and non magnetic state of a magnetic object changeable? Justify with reasoning.
18Is there any relation between electricity and magnetism? Make it clear by giving the example of one activity.
19The electricity meter fitted in Bhawana's house read a consumption of 75 units in 15 days, and Rs 9.5 has to be paid to the electricity authority for each unit. Calculate how much the bill for one month will be.
20Eight bulbs of 25 W fitted in a house are run for 4 hours 40 minutes each day. Calculate how many units of electricity the meter shows as the daily consumption.
21The submeter of the room where Sharmila studies showed a bill of 8.5 units in one month. If Sharmila lights a single 65 W bulb in that room only while studying, calculate how many hours she studies each day.
22In one neighbourhood of a municipality, 14 street lights of 1,500 W burn for 6.5 hours a day. If the authority charges the municipality Rs 12.5 for each unit, calculate the bill to be paid each month.
23Why are the lights of a house joined in parallel? Write three reasons.
24What happens when the middle bulb of three bulbs joined in parallel is taken out of its holder? Why?
25Why must the switch be placed on the phase wire, and why must every bulb have a switch of its own?
26Why is a series connection not considered suitable for the lights of a house?