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प्रश्न
State the position of heating element with respect to principal focus of concave reflector and give reason for choosing this position.
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उत्तर
The heating element is between the pole and principal focus of concave reflector. This in turn, gives rise to a divergent beam of heat radiations.
संबंधित प्रश्न
Define kilowatt-hour.
Name two gases which are filled in filament type electric light bulbs.
Distinguish between kilowatt and kilowatt-hour.
A coil of copper wire is connected to a galvanometer. What would happen if a bar magnet is:
(i) Pushed into the coil with its north pole entering first?
(ii) Held at rest inside the coil?
(iii) Pulled out again?
Why is heating coil wound in the form of a helix in electric stove?
What are the two main systems of wiring commonly used in houses? Which of these systems mentioned by you is better and why?
What changes in energy occur in an electric bulb?
How does earthing prevent electrical shock?
An electric bulb is rated 240V-60W and is working at 100% efficiency.
(i) Calculate the resistance of bulb.
(ii) (a) Draw the circuit diagram.
(b) What is the rate of conversion of energy in each bulb?
(c) Total power used by the bulbs.
