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