CBSE Class 7 Science Electric Current and its Effects MCQs

Question. A combination of two or more cells is called 
(a) A Battery
(b) A Button cell
(c) An Electric cell
(d) Truck Battery

Answer:  A

Question. When an electric circuit from the positive terminal of the battery to the negative terminal of the battery is complete, then the circuit is said to be 
(a) Closed
(b) OPen 
(c) No change
(d) Disconnected 

Answer:  A

Question. Current flows through the circuit when the circuit is in the ________condition. 
(a) Closed
(b) Open
(c) Broken 
(d) Incomplete 

Answer:  A

Question. An electric wire connected in a circuit gets heated up when current is allowed to flow through it . This is due to 
(a) Heating effect of current 
(b) Electrical effect of current
(c) Musical effect of current
(d) Optical effect of current

Answer:  A

Question. A glowing filament will be 
(a) At a low temperature
(b) At a high temperature
(c) At atmospheric temperature 
(d) At the temperature of ice

Answer:  B

Question. The heat energy produced by a glowing bulb can be minimised by using _____ bulbs in place of ordinary electric bulbs
(a) A candle
(b) CFL bulbs
(c) Torch
(d) Kerosene lamp

Answer:  B

Question. The wire which melts and breaks the circuit when large current is allowed to flow through it is called 
(a) A fuse wire
(b) Electric wire
(c) Connecting wire
(d) Filament

Answer:  B

Question. _________piece is attracted by an electromagnet
(a) Wood
(b) Iron 
(c) Plastic 
(d) Rubber 

Answer:  B

Question. An electromagnet is one which behaves as a magnet when current is ______ 
(a) Allowed to flow through 
(b) Not allowed to flowthrough
(c) Stopped from flowing through it

Answer:  A

Question. When the current flowing through the fuse wire exceeds the safety limit, then it will be ______ breaking the circuit.
(a) Melted away 
(b) Remains the same 
(c) Damages the circuit 
(d) Makes the circuit remain connecte

Answer:  A

Question. Who discovered that when a compass needle is kept nearer to an electric circuit in which current is flowing ,it deflects.
(a) Hans Christian Oersted 
(b) Michael Faraday 
(c) Galileo 
(d) Newton 

Answer:  A

Question. When electric current passes through a wire , it behaves like a magnet. This is the 
(a) Magnetic effect of current 
(b) Electrical effect of current
(c) Heating effect of current 
(d) Optical effect of current

Answer:  A

Question. Electric Bell works on the principle
(a) Electrical energy is converted into mechanical energy
(b) Electrical energy is converted into sound energy
(c) Mechanical energy is converted into sound energy
(d) Sound energy is converted into electrical energy. 

Answer:  B

Question. Choose the statement which is not correct in the case of an electric fuse.
(a) Fuses are inserted in electric circuits of all buildings.
(b) There is a maximum limit on the current which can safely flow through the electric circuits.
(c) There is a minimum limit on the current which can safely flow in the electric circuits.
(d) If a proper fuse is inserted in a circuit it will blow off if current exceeds the safe limit.

Answer:  C

Question. When electric current flows through a conductor, the conductor becomes
(a) liquid
(b) vapor
(c) hot
(d) cold

Answer:  C 

Question. An electric iron is an example of
(a) heating effect of current
(b) magnetic effect of current
(c) chemical effect of current
(d) physical effect of current 

Answer:  A

Question. Nichrome is used a coil of heater because
(a) It has high resistance and high melting point
(b) Low resistance and high melting point
(c) High resistance and low melting point
(d) None of the above

Answer:  A

Question. In making a battery
(a) positive terminal of one cell is connected to the negative terminal of the next cell
(b) positive terminal of one cell is connected to the positive terminal of the next cell
(c) negative terminal of one cell is connected to the negative terminal of the next cell
(d) none of the above

Answer:  A 

Question. Why are symbols used for electronic components?
(a) It makes it easier to draw the circuit diagrams
(b) It is essential to draw the circuit diagrams
(c) It helps to show the direction of flow of current in a circuit
(d) All of the above 

Answer:  A 

Question. The Compact Fluorescent Electric Lamp Has:
(a) Nichrome filament
(b) Chromium filament
(C) Tungsten filament
(d) No filament

Answer:  D 

Question. A coil of insulated currrent- carrying wire wound around a piece of a magnetic substance is:
(a) voltmeter
(b) magnetic coil
(c) electromagnet
(d) none of these

Answer:  C

Question. Which of the following precaution need not be taken while using electric appliances?
(a) Never touch lighted electric bulb connected to mains.
(b) Never experiment with the electric supply from mains.
(c) Never use any wire to replace fuse wire.
(d) Never turn switch in ‘ON’ position. 

Answer:  D 

Question. Which of the following is being used in place of fuses?
(a) MCB
(b) Nichrome
(c) Filament
(d) Switch 

Answer:  A 

Question. Bulbs, wires, cells and switches are known as the of a circuit.
(a) element
(b) switch
(c) filament
(d) none of these 

Answer:  A 

Question. Which of the following substance is conductor of electricity:
(a) rubber
(b) paper
(c) nails
(d) plastic 

Answer:  C 

Question. Electromagnet is based on
(a) Chemical effect of electric current
(b) Heating effect of electric current
(c) Magnetic effect of electric current
(d) Electro-chemical effect of electric current 

Answer:  C

Question. Arrangement of cells in a device is
(a) side by side
(b) one after the other
(c) (a) or (b)
(d) none of these 

Answer:  C 

Question. The magnetic material around the coil is wound is called:
(a) magnetic substance
(b) core
(c) soft iron
(d) none 

Answer:  B

Question. In A Filament Type Bulb, A Lot Of Electric Energy Is Wasted In The Form Of:
(a) Magnetism
(b) Sound
(C) Light
(d) Heat 

Answer:  D 

Question. Which of the following materials is a conductor?
(a) Silver
(b) Rubber
(c) Cloth
(d) Plastic 

Answer:  A 

Question. At The Time Of Short Circuit, The Current In The Circuit:
(a) Reduce substantially
(b) Does not change
(C) Increase heavily
(d) Varies continuously 

Answer:  C 

Question. The metal which is poor conductor of electricity is
(a) Gold
(b) Iron
(c) Aluminium
(d) Mercury

Answer:  D 

Question. The coil of wire contained in an electric heater is known as
(a) component
(b) element
(c) circuit
(d) spring 

Answer:  B 

Question. When Electric Current Is Passed Through The Filament Of A Bulb, It Gives Off:
(a) Sound and heat
(b) Heat and magnetism
(C) Heat and light
(d) Light 

Answer:  C 

Question. Fuse wire is generally made of
(a) tin and lead
(b) nickel and chromium
(c) nickel and copper
(d) chromium and silver 

Answer:  A 

Question. Start To Your Left Side, Three Bulbs A, B, C Are Connected In A Circuit With The Help Of Wire, Switch And Three Cells. There Are No Defected Pieces Of Anything. If Switch Is ON Position:
(a) Bulb C will glow first.
(b) Bulb B and C will glow simultaneously and bulb A will glow after sometime.
(C) All the bulbs A, B and C will glow at the same time.
(d) The bulbs will glow in order A, B and C.

Answer:  C

Question. Electromagnet loses its magnetic property when
(a) Current is very high
(b) Current is switched OFF
(c) Heat is increased
(d) Current is switched ON

Answer:  B