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Question
The following appliances are to be used on 240 V supply. Calculate the current used by each and say which fuse, 2 amp, 5 amp or 13 amp should be incorporated with each, (i) A television rated at 150 W, (ii) An electric iron rated at 750 W, (iii) An immersion heater rated at 3000 W, (iv) A hair dryer rated at 500 W. How much will it cost to run the television set for 100 days for an average of 4 hours a day at 60 paise per unit?
Solution
We know that P =VI
`"I" = "P"/"V"`
Given voltage supply= 240 Volt
(i) Current through television = `150/240` = 0.625 A
Thus, a fuse of rating 2 A should be used with it.
(ii) Current through electric iron = `750/240` = 3.125 A
Thus, a fuse of rating 5 A should be used with it.
(iii) Current through immersion heater = `3000/240` = 12.5 A
Thus, a fuse of rating 13 A should be used with it.
(iv) Current through hair dryer = `500/240` = 2.08 A
Thus, a fuse of rating 5 A should be used with it.
(v) Energy consumed by t.v. set in 100 days when used for 4 hrs per day
= `150/1000 xx 4 xx 100` = 60 kWh
Cost of running it for 100 days @Rs. 0.6 per unit= 60 x 0.6 =Rs 36
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