The Power of Electricity

                The Power of Electricity

Ø What happens to the television if you switch off the button? Why does it

     Stop  ?

     it stops because the supply of energy is cut off, no electricity supply, no

     power supply.

Ø Do you like playing games on mobile phones? (yes/ no)

Ø What happens to a mobile phone when it does not have any power?

     It switches off.

Ø How do you recharge the mobile phone to regain its power?

       with help of a Charger.

Ø Where does this charger get its energy or power from?

       Electricity, electric  Current.

Ø Give the uses of the following items in our daily life.

      ® refrigerator (keep thing cool) 

     ® air conditioner (cooling)

     ® microwave (cooking food)

    ® geyser (heating water)

    ® computer ( playing games, office work)

   ® electric iron  (ironing clothes)

Ø What is common regarding all these appliances?

      They all work on  electricity.

Ø Which other places other than our homes is electricity used?

School, supermarket, shops, factories, hospitals, offices, airport, railways etc.

Ø What are the ways we can save electricity/ reduce the wastage of

Electricity ?

® Switch off light when not needed

® unplug the electrical appliances from the main switch

® Turn off your monitor and set your computer to sleep mode whenever you're

     not  using it;

® Turn lights off when you leave a room and use spot lighting to illuminate

    specific areas rather than whole rooms.

Ø Name the scientist know for his famous lightning experiment?

     Benjamin Franklin.

Ø Why was this experiment dangerous? (as Benjamin Franklin got electric

     Shock  , he could have died.

Ø Name few sources of energy used to generate electricity?

    Oil, gas, coal ,wood, solar, nuclear, water power).

Ø  What  do you observe? 

    light

Ø What happens to the bulb?

   It glows.

Ø What happens to the bulb?

   It does not glow.

   · Open the back cover of the torch to remove the cells (batteries), replace the

     Back  cover.

Ø Does the bulb light up?  

      No.

Ø Why?

     Because the batteries/ cells have been removed.

Ø Give names of some equipment that also use electric cells?

      Clock, wrist watches,

Ø What are the components of a torch?

Switch, dry cells/ electric cells and bulb

Ø  Name the terminals of a dry cell?

      Positive and negative terminal.

Ø When does an electric cell stop producing electricity?

      When the chemicals inside the cell are used up.

Ø Name the dry cell that can be recharged?

    Secondary cell.

Ø Give example of lead- acid accumulators?

   Car batteries  alarm clocks, toys, etc.

Ø How does an electric cell produce electricity?

    Electric cell produce  electricity from chemicals stored inside it.

Ø What is an electric cell used in cameras and torches also called as?

     Dry cell.

Ø Will the bulb of a torch light up if the electric cells are removed from the

torch?

    No

Ø Where else do we use electric bulbs?

    lamps, rooms, lighting, etc.

Ø Which part of the bulb glows?

Tiny coiled wire in the middle of the bulb glows.

· The tiny coiled wire that gives off light is called filament, electricity passes through the filament as a result it gets heated up and gives out light.

when more than one cell is connected in the circuit the bulb will be brighter as more current will pass into

the circuit, but the cells will very soon be used up since

More current = shorter life.

Less current = longer life.

Ø What is filament

The tiny coiled wire that gives off light is called filament.

Ø Why is tungsten used to make the filament of a bulb?

Tungsten has high melting point, it does not melt even when the filament glows at a very high

Temperature.

Ø In what way are the two terminals of the bulb useful?

When the two terminals are joined to an electric cell, the electric current flows through the

filament which gets heated up and starts glowing.

An electric bulb will light up only when the circuit is complete i.e. the

path  through which the electric current flows is:

® Not broken

® Or none of the components are missing

® Or there is no gap in the circuit.

Ø Will the bulb glow, if one terminal of a cell is connected using a wire and the

other terminal of the cell is not connected?

No, bulb will not glow.

Ø Why do you think the bulb will not glow in this case?

Because electricity/ electric current will not flow through the circuit.

Ø What do you do when you want to turn off light in your room? (switch them/ it

off).

Ø Define electric circuit.

The complete path from one terminal of an electric

cell through the bulb and back to the other terminal of the electric cell is

called electric circuit.

 Ø What is electric switch?

It is a device used for making or breaking a circuit.

Ø What do you understand  by a fused bulb?

When the filament of a bulb breaks, the electric circuit is no more complete, since no current can pass

through the filament now, the bulb does not glow and is thus called a fused

bulb.

Ø Even when the circuit was complete, why didn’t the bulb glow?

Because the plastic is an insulator, it does not allow electricity to pass through it.

Ø Will the bulb glow, if the plastic scale was replace with a scale made of

some metal? Why?

Yes, because metals are good conductor of electricity.

Ø Why did the bulb glow even on adding the iron nail in the circuit?

As iron is a metal and it is good conductor of electricity.

Ø What would be the reason to use such wires instead of direct copper/ or any

metal wire?

Metals are good conductors and will give us electric shock,

plastic coating saves us from shock.