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Electricity and Circuits Extra Questions




In this page we have Chapter 12 Electricity and Circuits Extra Questions . Hope you like them and do not forget to like , social share and comment at the end of the page.
Question 1
SHORT ANSWER TYPE QUESTION
  1. Complete the drawing shown below to indicate where the free ends of the two wires should be joined to make the bulb glow

  2. Why do electrician wear rubber hand gloves while working with electricity?
  3. What are the advantages of a dry cell?
  4. Why we should not operate electric switches with wet hands?
  5. 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.
  6. Why Electric wires are made of copper?

Answer

(a)
(b) Electricians wear rubber hand gloves while working with electricity because rubber is a bad conductor of electricity.
(c) Dry cells have the following advantages:
(i) Dry cells can be easily transported from one place to another.
(ii) Dry cells are very light in weight and small in size.
(iii) Dry cells can be easily stored in houses.
(d) Water is a good conductor of electricity and we might get an electric shock if we operate electric switches with wet hand.
(e) Yes, if the object is good conductor of electricity then current will pass through conduction tester and the bulb will glow. Hence the object will be a conductor of electricity. (f)Copper is a good conductor of electricity so Electric wires are made of copper.


Question 2
SHORT ANSWER TYPE QUESTION/HOTS.
  1. What are the essential components of an electric circuit?
  2. What is a conductor? Give two examples.
  3. What alternative devices can we use if there is a sudden breakdown of electric supply?
  4. Why do bulbs have two terminals?
  5. What is current?
  6. How can you generate electricity from sunlight?
  7. Mention three drawbacks of voltaic cell?
  8. Name two sources of electric current.
  9. What is meant by battery?
  10. What is the function of the switch in an electric circuit?
  11. Why is distilled water used in the batteries and not the tap water?
  12. What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.
  13. Answer

    (a)The essential components of an electric circuit are a conducting wire, battery or cell and a key.
    (b)The materials which allow current to pass through them are called conductors. For examples, Copper, Aluminium
    (c)Generators and inverters
    (d)Bulb has two terminals to connect the filament with the circuit so that the current can pass through it.
    (e)The rate of flow of electric charge through a conductor per unit time is called electric current.
    (f)we can generate electricity from sunlight with the help of solar cell.
    (g)1. They are generally non-rechargeable
    2. Expensive
    3. Not long lasting
    (h) Voltaic cell & Daniel cell
    (i) The positive terminal of one cell is kept in contact with the negative terminal of the other cell. When two or more cells are joined together in this way, we get a battery.
    (j) The function of switch in an electric circuit is to either make or break the electric circuit. A switch is used to turn current to an electrical appliance either on or off.
    (k) Because distilled water acts as an insulator as it is purest water. Whereas tap water has salts and impurities and acts as a conductor.
    (l) A switch is used to complete or break an electric circuit to use an electric appliance according our convenience. Some electrical gadgets that have switches built into them are electric lamps, cooler, washing machines.


    Question 3
    LONG ANSWER TYPE QUESTIONS.
    (a)Differentiate between conductors and insulators.

    Answer

    Conductors
    Insulators
    They allow electricity to pass through them.
    They do not allow electricity to pass through them.
    They have electric charges free to move.
    They have electric charges which are not free to move.
    When some charge is transferred to a conductor, it readily distributes over the entire surface.
    When some charge is transferred to an insulator, it remains at the same place over the surface.
    Most metals are conductors.
    Most non-metals are insulators


    (b)
    (i)What is an insulator? Give two examples
    (ii)Give one activity to prove that air is an insulator.
    (iii) Write few uses of insulators

    Answer

    i. The materials that do not allow electric current to pass through them are called insulators. For examples, plastic & Wood.
    ii. Take an electric circuit, keep the terminals unconnected in the air. The bulb do not glow, as air is an insulator and does not allow the current to flow through it.
    iii. Insulators are used in making switchboard, handles of testers, screw drivers.


    (c)
    i. Explain why the bulb would not glow in the arrangement shown in the figure below.
    ii. What steps can you take to make it glow. Explain with diagram.

    Answer

    i. In the given arrangement, a tester is also connected in the circuit. The tester holder is made of plastic which is a bad conductor of electricity. Thus, current cannot flow through the circuit. Hence, the bulb would not glow.
    ii. we have to remove the tester and connect the wire attached to the both ends of the tester, it will complete the circuit, and the bulb will glow.



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