A meniscus lens is made of a material of refractive index mu_(2).Both its surfaces have radii of curvature R.It has two different media of refractive indices mu_(1)and mu_(3)respectively ,on its two sides (See figure) .Calcualte its focal length for mu_(1)ltmu_(2)ltmu_(3),when light is incidence on it as shown

A meniscus lens is made of a material of refractive index mu_(2).Both

1.	A meniscus lens is made of a material of refractive index mu_(2).Both its surfaces have radii of curvature R.It has two different media of refractive indices mu_(1)and mu_(3)respectively ,on its two sides (See figure) .Calcualte its focal length for mu_(1)ltmu_(2)ltmu_(3),when light is incidence on it as shown
Answer» Solution : `(mu_(2))/(v)-(mu_(1))/(OO)=(mu_(2)-mu_(1))/(R )` `v=(mu_(2)R)/(mu_(2)-mu_(1))`this IMAGE will act as OBJECT for second refraction. `(mu_(3))/(v)-(mu_(2)(mu_(2)-mu_(1)))/(mu_(2)R )=(mu_(3)-mu_(2))/(R ) RARR (mu_(3))/(v)=(mu_(2)-mu_(1))/(R )+(mu_(2)-mu_(1))/(R )` `(mu_(3))/(v)=(mu_(3)-mu_(1))/(R ) rArr v=(mu_(3)R)/((mu_(3))-mu_(1))` `f=(mu_(3)R)/((mu_(3)-mu_(1))`