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प्रश्न
The diagram shows two ways of connecting three lamps P, Q and R to A.C. supply of 220 V.
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उत्तर
The arrangement is shown in the figure (i) is a series arrangement. The arrangement in figure (ii) is the parallel arrangement.
We prefer a parallel arrangement. The reasons are:
(i) In series arrangement, if one of the bulbs is fused, the other bulbs also cease to glow. But in a parallel arrangement, if one bulb fuses, the other bulbs continue to glow.
(ii) In the series arrangement, while one bulb glows if the other bulb is switched on, the resistance of the circuit increases, and hence the bulbs glow less bright. But in a parallel arrangement, each bulb glows at the same voltage, therefore the glow of a bulb is unaffected if another bulb is switched on.
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संबंधित प्रश्न
Define the unit of current.
Choose the correct alternative and rewrite the following sentence.
When the resistance of a conductor increases, the current will ________ increase.
For a heater rated at 4 kW and 220 V, calculate:
(a) the current,
(b) the resistance of the heater,
(c) the energy consumed in 2 hours, and
(d) the cost if 1 kWh is priced at Rs 4.60.
Two lamps, one rated 40 W at 220 V and the other 60 W at 220 V, are connected in parallel to the electric supply at 220 V.
(a) Draw a circuit diagram to show the connections.
(b) Calculate the current drawn from the electric supply.
(c) Calculate the total energy consumed by the two lamps together when they operate for one hour.
Define the term resistivity.
Find the effective resistance in the following circuit diagrams (Fig.):
Fig. shows a 3 pin plug with the cover removed. The electric cable
connected to the plug contains 3 wires with colour coded insulation namely brown, blue and green.
- Identify each of the colour coded wires by stating to which of the
terminals A, B or C in the diagram they should be connected. - Identify the terminal through which no current passes in normal
circumstances. - What is the purpose of the earthed wire connected to an electric
appliance like an electric heater? Describe how it works.
A 3 pin mains plug is fitted to the lead for a 1 kW electric kettle to be used on a 250 V A.C. supply. Which of the following statements is NOT correct?
(a) A 13 A fuse is the most appropriate value to use.
(b) The brown wire should be connected to the live side of the mains.
What is meant by internal resistance of a cell?
Name any two devices, which are working on the heating effect of the electric current.
