A biconvex thick lens is constructed with glass (mu = 1.50). Each of the surfaces has a radius of 10 cm and the thickness at the middle is 5 cm. Locate the image of an object placed far away from the lens.

Explanation

Refraction at (1):
`mu_1=1,mu_2=(3)/(2),u=infty,R=10cm,v=?`
`(mu_2)/(v)-(mu_1)/(u)=(mu_2-mu_1)/(R)`
`((3)/(2))/(v)-(1)/(infty)=((3)/(2)-1)/(10)`
`v=30cm`
Refraction at (2):
`mu_1=(3)/(2),mu_1=1,u=(30-5)=25cm, R=-10cm,v=?`
`(1)/(v)-(1)/(25)=(1-(3)/(2))/(-10)`
`(1)/(v)-(1)/(25)=(1)/(20)`
`(1)/(v)=(1)/(20)+(1)/(25)=(9)/(100)`
`v=(100)/(9)`cm