A concave lens with unequal radii of curvature made of glass (μg = 1.5) has a focal length of 40 cm. If it is immersed in a liquid of refractive index μl = 2, then
1
it behaves like convex lens of 80 cm focal length
2
it behave like a convex lens of 20 cm focal length
3
its focal length becomes 60 cm
4
nothing can be said