Advertisements
Advertisements
प्रश्न
(a) Observe the diagram given below and state whether the bulb will glow or not when we switch on K.

(b) Is it safe to handle the bulb when the switch is OFF?
(c) Give a reason for your answer in (b).
Advertisements
उत्तर
- In the given figure it is observed that the bulb is connected with Live wire and the key is connected with Neutral wire. When the key or switch is ON, the path of current flow is completed, hence the bulb will glow.
- It is NOT safe to handle the bulb when the switch is OFF as bulb is directly connected to live wire.
- In the OFF position, the bulb remains connected to the high potential terminal through the live wire, but no current flows through the bulb, as the return path is incomplete. In this condition, it is not safe to touch the bulb even from outside. As a result, if the switch is connected to the neutral wire, it might be deceiving and even harmful to the user.
APPEARS IN
संबंधित प्रश्न
When current is switched ‘on’ in a room heater, it ______.
What is nichrome? State its one use.
Why are the coils of electric irons and electric toasters made of an alloy rather than a pure metal?
The electrical resistivities of four materials P, Q, R and S are given below:
| P | `6.84xx10^8`Ωm |
| Q | `1.70xx10^8`Ωm |
| R | ` 1.0xx10^15`Ωm |
| s | `11.0xx10^-7`Ωm |
Which material will you use for making: (a) heating element of electric iron (b) connecting wires of electric iron (c) covering of connecting wires? Give reason for your choice in each case.
Give Scientific reason.
In practice, the unit kWh is used for the measurement of electrical energy, rather than joule.
Name any two appliances which works on the phenomenon of heating effect of electric current.
A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross-section of the filament in 16 seconds would be roughly:
Unscramble the following words:
SFEU
Name two electric devices for each where
- heating effect of current is used and
- magnetic effect of current is used.
An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
