For an object at infinity, the focal length of a normal eye-lens is about

Q. The focal length of a normal eye-lens is about:

Q. The focal length of a normal and relaxed eye lens is about -

Q. An object is placed at a distance of 30 cm from a converging lens of focal length 15 cm. A normal eye (near point 25 cm, far point infinity) is placed close to the lens on the other side. (a) Can the eye see the object clearly? (b) What should be the minimum separation between the lens and the eye so that the eye can clearly see the object? (c) Can a diverging lens, placed in contact with the converging lens, help in seeing the object clearly when the eye is close to the lens?

Q. In a compound microscope the focal length of an objective lens is $1.2\text{cm}$ and the focal length of the eye piece is $3\text{cm}$. When the object is kept at $1.25\text{cm}$ in front of the objective lens, the final image is formed at infinity. Magnifying power of the compound microscope should be:

Q. In a compound microscope the focal length of objective lens is $1.2cm$ and focal length of eye piece is $3.0cm$. When object is kept at $1.25cm$ in from of objective, final image is formed at infinity. Magnifying power of the compound microscope should be :