Monday, October 22, 2012

Electricity and Electric Circuits for Class VI(CBSE)

Quest Time CBSE NCERT VI Chapter: Electric currents, Circuits, Cell.

For Questions 1 to 10 visit link: Class VI Physics By Jsunil

11. What conductors and insulators?

Ans: The materials which allow electric current to pass through them are called conductors. Examples: All metals like Copper,Iron, Silver and Human body.
INSULATORS: The materials which do not allow electric current to pass through them are called bad conductors or insulators. Examples: Plastic, Wood, Rubber and Glass.

12. Why do electricians wear rubber gloves and shoes while at work?

Ans: It because rubber gloves are an insulator and prevent current to flow in body .Thus saves electricians from electric shock.

13. What do you mean by heating effect of current?

Ans: Electric current is actually the flow of electrons in the conducting material. Now,
when these electrons flow, they encounter some resistance in the structure of the conductor, which accounts for the "resistance" of materials. As the electrons collide or vibrate, heat energy is generated depending on the resistance of the conductor. This overall effect is called heating effect of electrical current.

14. Name a few appliances that work on the heating effect of current?

Ans: Electric kettle: Used for boiling water to make tea or coffee
Electric bulb : The filament of the bulb is heated when current flows and becomes white hot to emit brilliant light.
Electric iron: Used for ironing or pressing clothes.  
Electric toaster: Used to toast bread

15. Name a special material used for heating component?

Ans: It is a coil of wire made of a special material called nichrome which becomes very hot when current is passed. This heat is used to cook food (as in an electric stove), heat water ( as in an electric kettle, electric heater) etc

16. Name the elements used to make an alloy nichrome?

Ans: Nickel and Chromium.

17 Why are electric wire are made up of copper through silver is best conductor?

Ans: Silver is an expensive metal. Material needed for conductor should be cheap as wires are used extensively in almost every appliance. That is why silver can't be used to make wires.

18. Why do you apply a tap over the joint of electric wire?

Ans: Tap is an insulator and save us from electric shock.

19. If you connect a battery cell to the bulb through a wooden stick, the will not glow. Why?

Ans: No, wooden stick is an insulator that cannot conduct electricity

20. Do not handle the electric appliances when your hands are wet. Why?

Ans: Tap water is good conductor and we may get electric shock.

21. There will be three colored wires normally used while connecting any electric equipment. What are those colors? Tell which coloured wire gives us electric shock?

Ans: Red (Live wire that give us electric shock), Black (Neutral) , and Green(Earth wire)

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