(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 ?

(i) A torch bulb is rated at 3V and 600 ma . Calculate it's (a) power

1.	(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 ?
Answer» Solution :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.