Two inductors of inductance 5 mll and 15 mll are connected in series and a current of 5A flows through them. the total energy stored in the inductor is?
500.0J
250.0J
62.5J
50.0J
no correct option
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This is how JAMB wants people to fail, picked B coz my answer is related with it, i thought they converted it
The answer is 250
solution: energy in an inductor (E)= 1/2×L×(i^2) where L is the inductance and i is the current
using the above formula 1/2×5×(5)^2= 62.5 [that's energy stored in the inductor with 5mh inductance is 62.5j)
then looking for energy stored in15mh we have 1/2×15×(5)^2=187.5j
then to get the total energy stored in the two inductors we add both of them together 187.5j+62.5j=250j final answer
hope this helps, jamb here we come God no go shame us
basically, inductance is measured in Henry so once you see mill in your question.....kindly convert to Henry(H)by ÷1000
E=1/2LI²
E=?
L= 5×10³ + 15× 10³(change to standard form by dividing by 1000 for easy solving)
= 0.005+0.015
=0.02
I=5
E= 1/2×0.02×5²
= 1/2×0.02×25
= 0.5/2
=0.25J
NOTE:I DIVIDED BY 1000 CUS IT'S 10³.
You can choose to solve without converting it at the initial stage.
You just solve straight then divide your answer by 1000, but the method I used is safer.
The answer should be "1j"
L=mh(5+15)
L=20mh=20/1000h=0.02
I=5A
Energy =1/2Li²
Energy=1/2×0.02×5²
=1/0.04×25
=1/1
=1J
