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(i) A torch bulb is rated at 3V and 600 ...

(i) A torch bulb is rated at 3V and 600 ma . Calculate it's (a) power (b) resistance
(c) energy consumed if it used for 4 hours.
(ii) Why does sound travel faster on a rainy day than on a dry day ?

Text Solution

Verified by Experts

Given
V = 3 V
I = 600 mA = `600 xx10^(-3) A`
(a) Power (P) = VI = `3xx 600 xx10^(-3) = 1800xx10^(-3)`
= P = 1.8 W (or) watt.
(b) Resistance `(R) =V/I`
`R = (3)/(600xx10^(-3) ) =(3xx10^3)/(600)=3000/600`
(c) Power P = 1.8 W and t = 4 hours
`4 xx60xx60=14400` second
Energy consumed `(E) = P xxt `
` = 1.8xx14400=25920` joules
E = 25. wh
(ii) When humidity increase the speed of sound increase . That is why we can hear sound from long distance clearly during rainy season.
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