Electricity and Circuits

Q1. Fill in the blanks.

                          i.        Insulators do not allow current to pass through them.

                         ii.        Air is an insulator.

                        iii.        Our body is a good conductor of electricity.

                        iv.        The metal cap is the positive terminal of the electric cell.

Q2. True/False

                          i.        Impure water can also conduct electricity. True

                         ii.        An electric cell produces electricity from the chemicals stored inside it. True

                        iii.        The metal disc is the positive terminal. False

                        iv.        Brass is a conductor. True

                        v.        Insulators allow current to pass through them. False

Q3. Which device is used to open or close an electric circuit?

Ans. Electric switch

Q4. Who invented the first electric bulb?

Ans. Thomas Alva Edison invented the first electric bulb.

Q5. Who invented the first electric cell?

Ans. Alessandro Volta invented the first electric cell.

Q6. Which is the +ve terminal of a cell?

Ans. The metal cap is the positive terminal of the electric cell.

Q7. Which is the –ve terminal of a cell?

Ans. The metal disc is the negative terminal of the electric cell.

Q8. Who invented dry cell?

Ans. French chemist Georges Leclanche invented dry cell.

Q9. Define an electric switch.

Ans. A switch is a simple device that either breaks the circuit or completes it.

Q10. Where does the torch get electricity from?

Ans. Electricity to the bulb in a torch is provided by the electric cell.

Q11. Where does electricity come from?

Ans. A power station provides us with electricity.

Q12. How does an electric cell produce electricity?

Ans. An electric cell converts chemical energy into electricity.

Q13. Name the type of circuit in which switch is in ‘OFF’ position.

Ans. Open circuit

Q14. Can distilled water conduct electricity?

Ans. No, distilled or pure water does not conduct electricity.

Q15. Name the type of circuit in which switch is in ‘ON’ position.

Ans. Closed circuit or complete circuit

Q16. Can tap water or rain water conduct electricity?

Ans. Yes, tap water or rain water can conduct electricity.

Q17. What is a thin wire fixed in the middle of the glass bulb called?

Ans. A thin wire fixed in the middle of the glass bulb is called a filament.

Q18. What is a filament in a light bulb?

Ans. The thin wire that gives off light is called the filament of the bulb.

Q19. Write two examples of conductor and insulators.

Ans. Conductor – Copper and Aluminium

        Insulators – Plastic and Rubber

Q20. What is heating effect of current?

Ans. Heating caused due to conversion of electrical energy into heat energy is called heating effect of current.

Q21. Will the bulb glow in an open circuit? Why or why not?

Ans. Bulb does not glow in an open circuit because the bulb glows only when current flows through the circuit.

Q22. What is an electric bulb?

Ans. An electric bulb (or a light bulb) is a device that converts electrical energy into light energy.

Q23. What are the two terminals called in an electric cell?

Ans. All electric cells have two terminals; a positive terminal and a negative terminal.