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+1 vote
11.7k views
in Physics by (69.9k points)

A bulb is marked 100W, 220V and an electric heater is marked 2000W, 220V. 

(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?

1 Answer

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by (72.7k points)
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Best answer

In the case of heater current = w/v = 2000/220 = 9.09A.

Hence power-voltage rating help us in this case. The current through the bulb is only 0.45A while through the heater it is 9.09A. Hence a heavy lead (to avoid power loss due to heating effect) is needed for the heater which for a bulb an ordinary thin connecting wire is required. 

(iii) Electric heater requires a thicker wire of lead.

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