Answers

2016-02-18T16:28:19+05:30
Hello !
if there are two lenses in contact both of focal length f₁ and f₂ then the resultant focal length will be : -
1/f = 1/f₁ + 1/ f₂
f₁ = 10 units
f₂ = -5 units 
then 
1/f = 1/10+(1/-5)
⇒1/f = 1 / 10 - 1/ 5
⇒1/f = (1-2)/10
f = -10 units                                                            Ans.
I hope my answer is correct !
Any problem please consult me 
And if u r satisfied please mark my answer as the best !
Thankyou!
0