A torch bulb is rated at 3V and 600mA. Calculate it’s (a) Power b) Resistance c) Energy consumed if it is lighted for 4 Hrs.
V = 3 V I = 600 mA = 600×10−3A600×10-3A (a) Power (P) = VI = 3×600×10−3=1800×10−33×600×10-3=1800×10-3 = P = 1.8 W (or) watt. (b) Resistance (R)=VI(R)=VI R=3600×10−3=3×103600=3000600R=3600×10-3=3×103600=3000600 (c) Power P = 1.8 W and t = 4 hours 4×60×60=144004×60×60=14400 second Energy consumed (E)=P×t(E)=P×t =1.8×14400=25920=1.8×14400=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.
