Advertisements
Advertisements
प्रश्न
You are required to connect a bulb, a fan and a socket outlet to the mains in one set A and an air-conditioner and a refrigerator to the mains in other set B. Will you recommend the wire of same thickness and same insulation in both? explain your answer.
Advertisements
उत्तर
No. The wire used in set B must be thicker and of better insulation than that used in set A. The reason is that in set B, the appliances will draw heavy current (= 15A) when they are used, whereas in set A, the appliances will draw ordinary current (= 5A) when they are in use. Therefore, the resistance of wire used in set B must be less than that of wire used in set A. A thick wire has less resistance than a thin wire.
संबंधित प्रश्न
Name the quantity whose unit is (i) kilowatt, and (ii) kilowatt-hour.
Which quantity has the unit of watt?
An electric kettle for use on a 230 V supply is rated 3000 W. For safe working, the cable connected to it should be able to carry at least:
(a) 2 A
(b) 5 A
(c) 10 A
(d) 15 A
State the position of heating element with respect to principal focus of concave reflector and give reason for choosing this position.
An electric bulb is marked 100 W, 230 V. What does this mean?
How does the heat produced by die passage of current in a metallic wire depend on the time of passage of current in the wire?
The equation I2R seems to suggest that the rate of heating in a resistor is reduced if resistance decreases, whereas equation P = V2/R suggests just the opposite. How do you reconcile this problem?
An electric appliance is rated at 1000 W, 250V. Calculate:
(i) The electrical energy consumed by the appliance in 12 hour.
(ii) The cost of energy consumed at Rs. 1.20 per kWh.
How long would this appliance take to use 1 kWh energy when operated at 250 V?
A family uses 8 kW of power. Direct solar energy is incident on the horizontal surface at an average rate of 200 W per square meter. If 20% of this energy can be converted to useful electrical energy, how large an area is needed to supply 8 kW?
