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प्रश्न
State (i) the S. I. unit, (ii) the household unit, of electrical energy. How are these units related?
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उत्तर
(i) The S.I. unit of electrical energy is joule (J)
(ii) The household unit of electrical energy is kilo-watt hour (kWh).
Relationship: 1 kWh = 1 kW × 1h
= 1000W × 3600 s
= 3.6 × 106 J.
संबंधित प्रश्न
1 kWh = ________ J
The table below shows the current in three different electrical appliances when connected to the 240 V mains supply:
| Appliance | Current |
| Kettle | 8.5 A |
| Lamp | 0.4 A |
| toaster | 4.8 A |
- Which appliance has the greatest electrical resistance? How does the data show this?
- The lamp is connected to the main supply by using a thin, twin-cored cable consisting of live and natural wires. State two reasons why this cable should not be used for connecting the kettle to the mains supply.
- Calculate the power rating of the kettle when it is operated from the 240 V mains supply.
- A main takes the kettle abroad where the mains supply is 120 V. What is the current is the kettle when it is operated from the 120 V supply?
Electrical power P is given by the expression P = (Q × V) ÷ time. What do the symbols Q and V represent?
A servo voltage stabiliser restricts the voltage output to 220 V ± 1%. If an electric bulb rated at 220 V, 100 W is connected to it, what will be the minimum and maximum power consumed by it?
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.
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State two advantages of filling an inert gas in an evacuated electric filament lamp.
Two bulbs are rated: bulb A 100W, 120 V bulb B 10W, 120 V. If both are connected across a 120V supply, which bulb will consume more energy, When in series? Also calculate the current through each bulb in above cases.
The electrical power and current in the circuit relates by ______
