Advertisements
Advertisements
Question
State the position of heating element with respect to principal focus of concave reflector and give reason for choosing this position.
Advertisements
Solution
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.
RELATED QUESTIONS
Which one has a higher electrical resistance : a 100 watt bulb or a 60 watt bulb?
The commercial unit of energy is :
(a) watt
(b) watt-hour
(c) kilowatt-hour
(d) kilo-joule
An electric heater of resistance 8 Ω takes a current of 15 A from the mains supply line. Calculate the rate at which heat is developed in the heater.
What is wrong with the circuit diagram (Fig. 34)? Carefully check the symbols and assign proper positive and negative signs to them.
An electric filament lamp is connected to a supply of voltage higher than the recommended value. Give reasons, why compared with a normal performance, the lamp emits a brighter light and its life is shortened.
Find the cost of operating an electric toaster for two hours if it draws 8 A current on a 110 volt circuit. The cost of electrical energy is Rs. 2.50 per kWh.
1 kWh = ____________
If a heater coil rated lkW, 220 V is connected in series with an electric bulb of 100 W, 220 V and are supplied 200V, power consumed by the bulb in this circuit is ______.
What is the meaning of electric power of an electrical device? Write its SI unit.
Two heaters A and B have power rating of 1 kW and 2 kW, respectively. Those two are first connected in series and then in parallel to a fixed power source. The ratio of power outputs for these two cases is ______
