two lamps one rated 100w at 220v and the other 200w at 220v are connected (i) in series and (ii) in parallel to the electric main supply of 220v. Find the current drawn in each case.
No spam this time please...
Share
two lamps one rated 100w at 220v and the other 200w at 220v are connected (i) in series and (ii) in parallel to the electric main supply of 220v. Find the current drawn in each case.
No spam this time please...
Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Explanation:
power =work done/time taken
P=w/t
we know v=w/q
w=vq
P=vq/t
q/t=i
P=VI
i=v/r
P=V^2/R
R=V^2/P
R1=v^2/p1
R1=220×220/100
R1=484 ohm
R2=V^2/P1
R2=220×220/200
R2=242 ohm
1. in series Reff=R1+R2
=484+242
Reff=726 ohm
i=v/R
i=220/726
i=0.30A
2.in parllel Reff =R1.R2/R1+R2
Reff=484/3 ohm
i=220/(484/3)
i=1.3A
P 1 =100
V 1 = 220 V
we know that ,
P 1=V²1/R 1
R 1 = V 1 ² /P 1
R 1= 48400/100
R 1= 484 ohm
R 2= V 2 ²/ P2
R 2 = 48400/200
R 2= 242 ohm
(1) R 1 and R 2 are connected in series
Rs = R 1 +R 2
R s = 242 +484
Rs = 726
I = V /R
I = 220 / 726
I =0 .30 A
(2) R1 and R 2 are connected in parallel
Rp = R 1 × R2 /R 1 + R 2
R p = 484×242/726
Rp = 161.3 ohms
I = V/R
I = 220 / 161
I =1.36 A