Electricity and Circuits | Science 6th | Chapter 12 | Questions and Answers

JANDKNCERT | Science 6^th |

Electricity and Circuits | Science 6th | Chapter 12 | Questions and Answers

 

Chapter 12: Electricity and Circuits

Dear Students, in Chapter 11, you learnt about the Light, Shadows, and Reflections, in which you learnt about the objects that allow or does not allow the light to pass through, for example, opaque objects, transparent objects, translucent objects, and luminous or non-luminous objects.

In this chapter, you will learn about Electricity and Circuits. The following points will help you to understand this chapter easily.

• Electricity is a source of electricity.
• An electric cell has two terminals; one is called positive (+ ve) while the other is negative (- ve).
• An electric bulb has a filament that is connected to its terminals.
• An electric bulb glows when an electric current passes through it.
• In a closed electric circuit, the electric current passes from one terminal of the electric cell to the other terminal.
• The switch is a simple device that is used to either break the electric circuit or to complete it.
• Materials that allow the current to pass through them are called conductors.
• Materials that do not allow the current to pass through them are called insulators.

 

Let us try to answer some questions taken from the NCERT Book of Science Class 6th. This Exercise is taken from the same book.

 

Important Instructions and Precautions

Do not touch uncovered wires or unclaimed things. An uncovered wire may harm you and unclaimed thing might be an explosive. Both may cause accidents that will result in loss of life or loss of financial assistance. Kindly be careful while working with wires.

Additional Questions

Q1. What is electric current?

Ans: Electric current is the flow of electric charge (usually electrons) through a conducting path, such as a wire. It flows from the positive terminal to the negative terminal of a cell.

Q2. What is an electric cell?

Ans: An electric cell (or dry cell) is a device that produces a small amount of electricity by chemical reaction. It has two terminals: a positive terminal (metal cap) and a negative terminal (flat metal disc).

Q3. What is a dry cell?

Ans: A dry cell is a type of electric cell that contains a paste-like electrolyte instead of a liquid. It is commonly used in torches, clocks, remote controls, and toys.

Q4. What is a switch?

Ans: A switch is a device that opens or closes a circuit. When the switch is ON (closed), the circuit is complete and current flows. When the switch is OFF (open), the circuit breaks and current stops.

Q5. What is an electric circuit?

Ans: An electric circuit is a complete path through which electric current can flow. It includes a power source (like a cell), conducting wires, and devices such as bulbs or switches.

Q6. What is a conductor? Give examples.

Ans: A conductor is a material that allows electric current to pass through it. Examples: Copper, aluminum, iron, water with salts.

Q7. What is an insulator? Give examples.

Ans: An insulator is a material that does not allow electric current to pass through it. Examples: Plastic, rubber, wood, glass.

Q8. What happens if the circuit is not complete?

Ans: If the circuit is not complete (open), electric current will not flow and the device (like a bulb) will not work.

Q9. Why does a bulb light up when connected to a cell with wires?

Ans: The bulb lights up because the electric current from the cell flows through the wires and filament of the bulb, which produces heat and light.

Q10. Why should we never touch electric wires with wet hands?

Ans: Water is a conductor of electricity. Touching electric wires with wet hands can cause electric shock and is very dangerous.

 

Exercises

 

Q1. Fill in the blanks:

a. A device that is used to break an electric circuit is called ________.

b. An electric cell has ________ terminals.

Answer.

a. A device that is used to break an electric circuit is called a switch.

b. An electric cell has two terminals.

 

Q2. Mark ‘True or ‘False’ for the following statements:

a. Electric current can flow through metals.

b. Instead of metal wires, a jute string can be used to make a circuit.

c. Electric current can pass through a sheet of thermo Col.

Answer.

a. True

b. False

c. False

 

Q3. Explain why the bulb would not glow in the arrangement shown in the following figure.

 

Answer.

In the above figure, the bulb would not glow because one end of the wire is connected to the plastic part of the screwdriver. Plastic is an insulator and does not allow the current to pass through it; hence the bulb did not glow in the circuit.

 

Q4. Complete the drawing shown in Fig 12.14 to indicate where the free ends of the two wires should be joined to make the bulb glow.

 

Answer.

Q5. What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.

Answer.

The purpose of using an electric switch is to either break the power supply of a circuit or allow the power supply to complete it. Almost all electric gadgets have inbuilt switches installed in them for safety because a switch is a safety device. Rice cookers, ovens, refrigerators, radios, televisions etc. have switches built into them.

 

Q6. Would the bulb glow after completing the circuit shown in Fig. 12.13 if instead of a safety pin we use an eraser?

Answer.

An eraser is an insulator so in the given figure the bulb would not glow because an insulator does not allow current to flow through it.

 

Q7. Would the bulb glow in the circuit shown in the following figure?

Answer.

 

Answer.

The bulb in the given figure would not glow because the two ends of the wire are connected to the same terminal of the bulb. The bulb will only glow if the positive end of the wire is connected to the positive terminal of the bulb and the negative end of the wire is connected to the negative terminal of the bulb.

 

Q8. Using the “conduction tester” on an object it was found that the bulb begins to glow. Is that object, a conductor or an insulator? Explain.

Answer.

If the bulb glows then the object is a conductor because only conductors allow current to pass in an electric circuit else it is an insulator if the bulb does not glow. While using the conducting tester on an object it was found that the bulb begins to glow hence the object is a conductor.

 

Q9. Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.

Answer.

Electricity causes severe injuries if touched with naked hands, hence electricians should use rubber gloves while repairing electric devices because rubber gloves are insulators and do not allow the current to pass through them thus protects electricians from electric shocks.

 

Q10. The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?

Answer.

The handles of the tools used by electricians for repair work have plastic or rubber covers because they are insulators and do not allow the electricity to pass through them and thus protects and saves them from electric shocks.

 Electric Circuit