Two lamps rated (100w, 220v) and (60w, 220v) are connected in parallel. which lamp consumes more energy and which one gives more brightness? Find the resistance of each lamp. ( Take supply voltage as 220 v).

Asked by niharikag_2004 | 3rd Jun, 2020, 04:00: PM

Expert Answer:

T h e space p o w e r space r a t i n g space o f space t h e space l a m p space 1 space i s space 100 space W space a n d space t h a t space o f space t h e space s e c o n d space l a m p space i s space 60 space W space
W i t h space t h i s space w e space c a n space s a y space t h a t space t h e space e n e r g y space c o n s u m e d space b y space l a m p space 1 space left parenthesis 100 W space l a m p right parenthesis space i s space m o r e space t h a n space t h e space s e c o n d space l a m p. space

W e space k n o w comma space
P space equals space V squared over R space
therefore P subscript 1 space equals space V squared over R subscript 1 space
100 space equals space 220 squared over R subscript 1 space
R subscript 1 space equals space 484 space capital omega space... left parenthesis r e s i s tan c e space o f space l a m p space 1 right parenthesis space

N o w comma space
therefore P subscript 2 space equals space V squared over R subscript 2 space
therefore R subscript 2 space equals space 220 squared over 60 space equals space 806.67 space capital omega space


 
As the resistance of the second lamp is more than the first lamp we can say that the lamp 1 (100 W lamp) glows with more brightness. 

Answered by Shiwani Sawant | 3rd Jun, 2020, 09:24: PM