(i) To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell.
(ii) When the electric current through the fuse exceeds a certain limit, the fuse wire melts and breaks.
(iii) An electromagnet does not attract a piece of iron.
(iv) An electric bell has an electromagnet.
Q.2. Fill in the blanks.
(i) Longer line in the symbol for a cell represents its ____ terminal.
(ii) The combination of two or more cells is called a ____.
(iii) When current is switched ‘on’ in a room heater, it ____.
(iv) The safety device based on the heating effect of electric current is called a ____.
Q.3. What is electric current?
Q.4. Who discovered magnetic effect of current?
Q.5. Which wire used in electric heater and why?
Q.6. Is it possible for a wire to melt and break? Why?
Q.7. Who invented electric bulb?
Q.8. Write some uses of battery.
Q.9. What is filament?
Q.10. What is the heating effect of the electric current?
Q.11. What are the uses of heating effect of electric current?
Q.12. Name any two effects of electric current.
Q.13. What is an electric circuit?
Q.14. Explain the symbol of electric cell.
Q.15. Why are fuse wires not used in circuit containing electric cell?
Q.16. Why a fused bulb does not glow?
Q.17. Why should we look for ISI mark on electrical appliances?
Q.18. We could not see element in electrical appliances. Give reason.
Q.19. Sometimes the cells are placed side by side. Then how are the terminals of the cells connected?
Q.20. On what factors does the heat produced in a wire depend?