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प्रश्न
Point out two main disadvantages of ‘Tree System’.
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उत्तर
The three main disadvantages are:
(i) Longer length of wire is required for wiring different rooms in a house. Since all circuits start from the main distribution board and so it is comparatively more Expensive.
(ii) If fuse blows off in any part of the building, it disconnects all the appliances in the circuit.
संबंधित प्रश्न
State the S.I. unit of electrical power.
When a current I flows through a resistance R for time t, the electrical energy spent is given by:
(a) IRt (b) I²Rt (c) `IR^2t` (d) `I^2R ⁄t`
An electric bulb is rated 250 W, 230 V. Calculate:
- the energy consumed in one hour
- the time in which the bulb will consume 1.0 kWh energy when connected to 230 V mains.
The diagram below shows a magnetic kept just below the conductor AB which is kept in North South direction.
(i) In which direction will the needle deflect when the key is closed ?
(ii) Why is the deflection produced ?
(iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB ?
(iv) Name one device which works on this principle.
What changes in energy occur in an electric heater?
State two advantages of filling an inert gas in an evacuated electric filament lamp.
An electric lamp A of 40 W and another electric lamp B of 100 W are connected to 220 V supply. Calculate the ratio of their filament resistances?
The resistance of filament of an electric heater is 500 Ω It is operated at 200V for 1 hour daily. Calculate the current drawn by the heater and the energy consumed in joule.
A torch bulb is rated at 3 V and 600 mA. Calculate it’s
- power
- resistance
- energy consumed if it is used for 4 hours.
