If two bulbs of 25 W and 100 W are rated @ 200V are connected in series across a 440 V supply then--
A. 100 W bulb will fuse
B. 25 W bulb will fuse
C. none of the bulb will fuse
D. both the bulbs will fuse
Pls show working.
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2 Answers
1since they are connctd in series........current is a constant
so
V/R is a constant
and also P/V is a constant
so...P1/V1=P2/V2
25/100=V1/V2
V2=4V1
and V=V1+V2
440=5V1
V1=88
and V2=352V
11See
P= V2/R
25 = 200*200/R
R = 1600
100 = 200*200/R
R = 400
Total Resistance = 2000
440 = I *2000
I = 0.22
I for 25 W is I2R =
25 = I2*1600
I = 5/40
I =1/8
I for 100
100 = I2*400
I = 1/2
Therefore 25W bulb will fuse b)
