1) Which of the devices use a battery? a) (a) Torch b) (b) Transistor c) (c) TV remote control d) (d) All of these 2) 2)Who discovered magnetic effect of current? a) (a) H.C. Oersted b) (b) Michael Faraday c) (c) Ohm d) (d) Flemming 3) Which mark is necessary on electric appliances? a) (a) ISI b) (b) FICC c) (c) AGMARK d) (d) KSK 4) When an electric current flows through a copper wire AB , the wire a) (a) deflects a magnetic needle placed near it. b) (b) becomes red hot. c) (c) gives an electric shock. d) (d) behaves like a fuse 5) Choose the statement which is not correct in the case of an electric fuse. a) (a) Fuses are inserted in electric circuits of all buildings. b) (b) There is a maximum limit on the current which can safely flow through the electric circuits. c) (c) There is a minimum limit on the current which can safely flow in the electric circuits. d) (d) If a proper fuse is inserted in a circuit, it will blow off if current exceeds the safe limit. 6) Three bulbs A, B, C are connected in a circuit, as shown in Figure 14.2. When the switch is ‘ON’ a) (a) bulb C will glow first. b) (b) bulb B and C will glow simultaneously, and bulb A will glow after some time. c) (c) all the bulbs A, B and C will glow at the same time. d) (d) the bulbs will glow in the order A, B and C. e) 7) Which of the following precautions need not be taken while using electric gadgets/appliances/circuits? a) (a) We should never touch a lighted electric bulb connected to the mains. b) (b) We should never experiment with the electric supply from the mains or a generator or an inverter. c) (c) We should never use just any wire or strip of metal in place of a fuse. d) (d) We should never turn the switch in ON position. 8) At the time of short circuit, the current in the circuit: a) a)reduces substantially b) b)does not change c) increases heavily d) varies continuously 9) n a quiz competition, you are asked a question where you have to choose the statement which is/ are incorrect? a) A fuse works on the heating effect of current. b) A fuse consists of a short length of a thin, tin-plated copper wire having low melting point. c) A fuse is a safety device which prevents electric fires and damage to electrical appliances due to excessive flow of current d) None of the above 10) Which of the following characteristic is not suitable for a fuse wire? a) thin and short b) thick and short c) low melting point d) higher resistance than rest for wiring 11) Read the following sentences carefully, and choose the incorrect one: a) An electromagnet works on magnetic effects of current b) Only iron is used for making electromagnets c) Magnetism in the coil remains as long as the current is flowing in the coil d) Steel is also used for making electromagnets 12) Vishvas is doing his homework which is given by his teacher. Would you help him to choose the incorrect sentences? a) The electric bell works on the heating and magnetic effect of current b) The electric bell has a U-shaped electromagnet c) The electric bell uses an electromagnet to pull that clapper on to a metal bell called gong. d) None of the above 13) Shreya is writing some statements but she confused to know whether the statements are correct or not? If you know the answer to this question, then tell her: a) Electromagnets are used in the construction of a large number of devices like electric bells, loudspeakers, electric motors etc. b) Electromagnets are used by doctors to remove tiny iron particles from the eyes of a person (which may have fallen into the eyes accidentally). c) ]. The electromagnets which are used for loading and unloading heavy iron and steel objects are fitted on cranes. d) ]. All the above 14) Consider the following statements and choose the correct one: a) Electricity is a form of energy. b) The flow of electricity through a conductor is called electric current. c) Electricity is useful because it can run many appliances in our day-to-day life which make our work easier. d) ]. All the above 15) The sound produced in a door bell is due to the: a) Chemical effect of current b) Heating effect of current c) Magnetic effect of current d) Sound effect of current 16) Which of the following does not work on the heating effect of current? a) [A]. Electric bulb b) [B]. Miniature circuit breaker c) [C]. Electric fuse d) [D]. Immersion rod 17) Which of the following is not a reason for excessive currents in electrical circuits? a) (a) Direct touching of wires b) (b) Short circuiting c) (c) Switch in ‘off position d) (d) Overloading 18) Fuse wire is generally made of a) (a) tin and lead b) (b) nickel and chromium c) (c) nickel and copper d) (d) chromium and silver 19) When electric current passes through a wire, it behave like a a) (a) battery b) (b) magnet c) (c) fuse d) (d) compass needle 20) The amount of heat produced in a wire depends on its a) (a) material b) (b) length c) (c) thickness d) (d) all of these

Quiz class 7

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