Electric Current And Its Effects Worksheet

Objective Type Questions

1. Match the following:
   
   

   	Column I		Column II
   I	Filament	A	safety device that melts and breaks an electric circuit during the time of overload or short circuit.
   II	Fuse	B	The effect of an electric current that causes a conductor to become hot
   III	Heating effect of electric current	C	The part of an electric bulb that gives off light when heated by an electric current
   IV	Electromagnet	D	A magnet that is created by passing an electric current through a coil of wire wrapped around a core of magnetic material

   
   State whether the statement is true or false: 
2. An electromagnet can be used to remove plastic bags from a garbage pile.  
   
   State whether the statement is true or false: 
3. The magnetic field of an electromagnet is always present in an electric bell, even when there is no electric current flowing through it. 
   
   
4. When an electric current flows through a wire, the wire gets heat up, this is known as _________.
   
   
5. Unscramble the following words: 
   A.TCRICUI
   B.RUTNREC
   C.LUSINOTAR
   
   
6. Observe the following figures, write the names and complete the diagram.
   
   
   Multiple Choice Questions
   
   
7. Which of the following devices uses electromagnets? 
   (a) Electric bells
   (b) loudspeakers
   (c) Junk separators
   (d) All of the above
   
   
8. Shiwani constructed an electromagnet by wrapping 50 turns of wire around an iron screw. Ram also created an electromagnet by winding 100 turns around a similar iron screw. Which coil will draw the most paper clips? 
   (a) Shiwani's coil
   (b) Ram's coil
   (c) Both will attract the same number of paper clips
   (d) Cannot be determine
   
   
9. The image represents an electric circuit with different components.
   
   Which of the marked components represents a switch in the circuit?
   (a) A
   (b) B
   (c) C
   (d) D
   
   
10. Which of these precautions must be followed while working with electricity? 
    (a) Always touch a lighted electric bulb to see if it is hot
    (b) Always pour water on a lighted electric bulb to cool it down
    (c) Always switch off the main power supply before replacing a light bulb
    (d) Always use a metal object to remove a broken light bulb from its socket 
    
    
11. A homeowner wants to prevent damage to their electrical appliances due to a sudden power surge. Which of these devices should be installed to avoid damages?
    (a) Miniature circuit breakers
    (b) Light-emitting diode
    (c) Compact fluorescent lamp
    (d) All of the above
    
    
12. Arun performs an experiment where he connects two bulbs, an incandescent bulb and a CFL, to the same power source and recorded the electric consumption. 
    What will be the most likely conclusion from his experiment?
    (a) Incandescent bulb will consume less electricity compared to CFL bulb.
    (b) CFL will consume less electricity compared to an incandescent bulb.
    (c) Both will use the same amount of electricity.
    (d) CFL will consume more electricity also it will produce more light compared to an incandescent bulb.
    
    Subjective Questions
    
    
13. Prachi and Rashmi both connect a wire of the same material and thickness to a circuit, but Rashmi’s wire is twice as long as Prachi’s wire.
    
    If the power source across both circuits is same, will the heat produced in both cases be equal? Justify your answer.
    
    
14. Rajiv wants to reset an MCB that has tripped due to overloading or short-circuiting in his home. What steps should he follow to safely reset the MCB?
    
    
15. The given image shows the arrangement of an electric circuit, 
    Case 1: 
    
    Case 2: 
    
    Draw an appropriate circuit diagram for both the cases.
    
    
16. As shown in the image, a student conducts an experiment in which he uses a copper coil to heat water. The water's initial temperature is measured to be 30°C. The student records the temperature of the water as 48°C after turning it on for 5 minutes. The water is allowed to cool back down to its original temperature.
    
    The activity is then repeated with a copper coil half the length of the first copper coil. He notices that the water temperature has reached 37°C after 5 minutes. What conclusions can we draw from the activity?
    
    Assertion-Reasoning Questions
    
    Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
    
    
17. Assertion: Rajiv advised Simran not to use wet hands to operate electrical appliances such as a hair dryer or an electric kettle.
    Reason: Water is a good conductor of electricity and can reduce the risk of electric shock.
    
    
18. Assertion- For an electric water heater wire of different materials, lengths, and thicknesses can be used to meet various requirements.
    Reason- The amount of heat produced in a wire depends on its material, length and thickness.
    
    
19. Assertion- To reduce the household consumption of electricity, the government of India offers a substantial subsidy on the purchase of LED bulbs.
    Reason- LED bulbs use less energy than incandescent bulbs, fluorescent tubes, or CFLs.
    
    Case-Based Questions
    
    
20. Sima performed an experiment where she placed a magnetic compass near a current carrying wire. She notices some deflection in the compass needle.
    
    (a) What does the deflection of the compass needle in Sima’s experiment indicate?
    (b) What would happen to the deflection of the compass needle in her experiment if she moved the compass further away from the wire?
    (c) What is the key observation she can draw from this experiment.
    (d) Now if Sima suddenly switches off the power supply, what will she most likely observe?

Objective Type Questions

1. Match the following:
   
   

   	Column I		Column II
   I	Filament	A	safety device that melts and breaks an electric circuit during the time of overload or short circuit.
   II	Fuse	B	The effect of an electric current that causes a conductor to become hot
   III	Heating effect of electric current	C	The part of an electric bulb that gives off light when heated by an electric current
   IV	Electromagnet	D	A magnet that is created by passing an electric current through a coil of wire wrapped around a core of magnetic material

   
   Correct answer: I – C, II – A, III – B, IV – D
   Solution:
   

   Column I	Column II
   Filament	The part of an electric bulb that gives off light when heated by an electric current
   Fuse	A safety device that melts and breaks an electric circuit during the time of overload or short circuit.
   Heating effect of electric current	The effect of an electric current that causes a conductor to become hot
   Electromagnet	A magnet that is created by passing an electric current through a coil of wire wrapped around a core of magnetic material

   
   State whether the statement is true or false: 
2. An electromagnet can be used to remove plastic bags from a garbage pile.  
   
   Correct answer: False
   Magnetic materials can be separated from non-magnetic materials using electromagnets. An electromagnet cannot separate plastic bags from a garbage pile because they are nonmagnetic materials.
   
   State whether the statement is true or false: 
3. The magnetic field of an electromagnet is always present in an electric bell, even when there is no electric current flowing through it. 
   
   Correct answer: False
   In an electric bell, an electromagnet's magnetic field is created by passing an electric current through a coil. The magnetic field vanishes when no electric current flows through it.
   
   
4. When an electric current flows through a wire, the wire gets heat up, this is known as _________.
   
   Correct answer: Heating effect of the electric current
   The wire gets hot when an electric current passes through it. This is the heating effect of the electric current.
   
   
5. Unscramble the following words: 
   A.TCRICUI
   B.RUTNREC
   C.LUSINOTAR
   
   Solution:
   (a)CIRCUIT
   (b) CURRENT
   (c) INSULATOR
   
   
6. Observe the following figures, write the names and complete the diagram.
   
   
   Solution:
   
   
   Multiple Choice Questions
   
   
7. Which of the following devices uses electromagnets? 
   (a) Electric bells
   (b) loudspeakers
   (c) Junk separators
   (d) All of the above
   
   Correct option: (d) – All of the above
   Solution: Electric bells, loudspeakers, and junk separators all use electromagnets.
   
   
8. Shiwani constructed an electromagnet by wrapping 50 turns of wire around an iron screw. Ram also created an electromagnet by winding 100 turns around a similar iron screw. Which coil will draw the most paper clips? 
   (a) Shiwani's coil
   (b) Ram's coil
   (c) Both will attract the same number of paper clips
   (d) Cannot be determine
   
   Correct option: (b) – Ram's coil
   Solution: Since the magnetic effect is directly proportional to the number of turns in the coil. Ram's coil has more turns than Shiwani's. So his electromagnet is more powerful than Shiwani's.
   
   
9. The image represents an electric circuit with different components.
   
   Which of the marked components represents a switch in the circuit?
   (a) A
   (b) B
   (c) C
   (d) D
   
   Correct option: (d) – D
   Solution:
   
   
   
10. Which of these precautions must be followed while working with electricity? 
    (a) Always touch a lighted electric bulb to see if it is hot
    (b) Always pour water on a lighted electric bulb to cool it down
    (c) Always switch off the main power supply before replacing a light bulb
    (d) Always use a metal object to remove a broken light bulb from its socket 
    
    Correct option: (c) – Always switch off the main power supply before replacing a light bulb
    Solution: Switching off the main power supply before replacing a light bulb is important to avoid the risk of electric shock.
    Whereas touching a lighted electric bulb can cause burns and pouring water on a lighted electric bulb can be dangerous. And using a metal object to remove a broken light bulb from its socket can cause electric shock.
    Hence the only correct option is (c).
    
    
11. A homeowner wants to prevent damage to their electrical appliances due to a sudden power surge. Which of these devices should be installed to avoid damages?
    (a) Miniature circuit breakers
    (b) Light-emitting diode
    (c) Compact fluorescent lamp
    (d) All of the above
    
    Correct option: (a) – Miniature circuit breakers
    Solution:   Miniature circuit breakers are designed to trip and cut off the flow of electricity if there is a sudden surge in power. This helps to protect electrical appliances from being damaged.
    
    
12. Arun performs an experiment where he connects two bulbs, an incandescent bulb and a CFL, to the same power source and recorded the electric consumption. 
    What will be the most likely conclusion from his experiment?
    (a) Incandescent bulb will consume less electricity compared to CFL bulb.
    (b) CFL will consume less electricity compared to an incandescent bulb.
    (c) Both will use the same amount of electricity.
    (d) CFL will consume more electricity also it will produce more light compared to an incandescent bulb.
    
    Correct option: (b) – CFL will consume less electricity than incandescent bulbs.
    Solution: CFLs are more energy-efficient than incandescent bulbs, and they produce more light while using less power compared to an incandescent bulb.
    
    Subjective Questions
    
    
13. Prachi and Rashmi both connect a wire of the same material and thickness to a circuit, but Rashmi’s wire is twice as long as Prachi’s wire.
    
    If the power source across both circuits is same, will the heat produced in both cases be equal? Justify your answer.
    
    Solution:
    No, the amount of heat produced in both wires will be different because the amount of heat produced in a wire when an electric current passes through it depends on its length, which is not equal for both cases.
    
    
14. Rajiv wants to reset an MCB that has tripped due to overloading or short-circuiting in his home. What steps should he follow to safely reset the MCB?
    
    Solution:
    To safely reset an MCB that has tripped due to overloading or short-circuiting, Rajiv should first switch off the main power supply to his home, then fix the cause of the overloading or short-circuiting, and finally switch the MCB back on.
    
    
15. The given image shows the arrangement of an electric circuit, 
    Case 1: 
    
    Case 2: 
    
    Draw an appropriate circuit diagram for both the cases.
    
    Solution:
    Case 1: 
    
    Case 2:
    Unlike case 1, the pin is removed from the circuit; hence it will be similar to a switch through which current cannot flow.
    
    
    
16. As shown in the image, a student conducts an experiment in which he uses a copper coil to heat water. The water's initial temperature is measured to be 30°C. The student records the temperature of the water as 48°C after turning it on for 5 minutes. The water is allowed to cool back down to its original temperature.
    
    The activity is then repeated with a copper coil half the length of the first copper coil. He notices that the water temperature has reached 37°C after 5 minutes. What conclusions can we draw from the activity?
    
    Solution:
    From the activity, we can conclude that the length of the copper coil affects the rate at which heat energy is produced. The longer copper coil generated more heat energy than the shorter one, resulting in a higher water temperature for the first case.
    
    Assertion-Reasoning Questions
    
    Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
    
    
17. Assertion: Rajiv advised Simran not to use wet hands to operate electrical appliances such as a hair dryer or an electric kettle.
    Reason: Water is a good conductor of electricity and can reduce the risk of electric shock.
    
    Correct option: (c) – A is true, but R is false.
    Solution: As we know, water is a good conductor of electricity and can increase the risk of electric shock. Hence, we should never touch any electrical appliances with wet hands.
    
    
18. Assertion- For an electric water heater wire of different materials, lengths, and thicknesses can be used to meet various requirements.
    Reason- The amount of heat produced in a wire depends on its material, length and thickness.
    
    Correct option: (a) – Both A and R are true, and R is the correct explanation of the assertion.
    Solution: As we know, the amount of heat produced in a wire depends on its material, length and thickness. Hence, we can use different materials, lengths, and thicknesses for an electric water heater to meet different requirements.
    
    
19. Assertion- To reduce the household consumption of electricity, the government of India offers a substantial subsidy on the purchase of LED bulbs.
    Reason- LED bulbs use less energy than incandescent bulbs, fluorescent tubes, or CFLs.
    
    Correct option: (a) – Both A and R are true, and R is the correct explanation of the assertion.
    Solution: Since LED bulbs consume less energy than any other bulbs (incandescent bulbs, fluorescent tubes and CFL bulbs). As a result, for the given case government of India offers a substantial subsidy on the purchase of LED bulbs to reduce household electricity consumption.
    
    Case-Based Questions
    
    
20. Sima performed an experiment where she placed a magnetic compass near a current carrying wire. She notices some deflection in the compass needle.
    
    (a) What does the deflection of the compass needle in Sima’s experiment indicate?
    (b) What would happen to the deflection of the compass needle in her experiment if she moved the compass further away from the wire?
    (c) What is the key observation she can draw from this experiment.
    (d) Now if Sima suddenly switches off the power supply, what will she most likely observe?
    
    Solution:
    (a) The deflection of the compass needle in Sima’s experiment indicates that a magnetic field is produced by the current flowing through the wire.
    (b) If Sima moved the compass further away from the wire in her experiment, the deflection of the compass needle would decrease, indicating a weaker magnetic field at that distance from the wire.
    (c) The key observation from this experiment is when an electric current passes through a wire, it behaves like a magnet.
    (d) Suppose Sima suddenly switches off the power supply. In that case, the current flowing through the wire will become zero because this magnetic field around the wire will vanish, and the compass will start pointing towards the north.