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प्रश्न
Why is the heating element of an electric oven wound on a helix? State the reason.
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उत्तर
In an electric oven, the china clay plate is provided either with lateral grooves or grooves in the form of a spiral helix. This type of spiral winding reduces the area of spread of nichrome wire and helps to concentrate heat in a small region.
संबंधित प्रश्न
Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V?
Define kilowatt-hour.
State whether an electric heater will consume more electrical energy or less electrical energy per second when the length of its heating element is reduced. Give reasons for your answer.
Which of the following is the most likely temperature of the filament of an electric light bulb when it is working on the normal 220 V supply line?
(a) 500°C
(b) 1500°C
(c) 2500°C
(d) 4500°C
Distinguish between kilowatt and kilowatt-hour.
A bulb is marked 100W, 220V and an electric heater is marked 2000 W, 220 V.
(i) What is the ratio between the resistances of these two devices?
(ii) How does the power-voltage rating of a device help us to decide about the type of leads (connecting wires) to be used for it?
(iii) In which of the above two devices, a thicker connecting wire of lead is required?
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.
