A student can distinctly see the object upto a distance `15 cm`. He wants to see the black board at a distance of `3m`. Focal length and power of lens used respectively will be

A person is unable to see objects nearer than 50 cm. He wants to read a book placed at a distance of 25 cm. Find the nature, focal length and power of the lens he requires for his spectacles.

A person with myopia can see objects plaecd at a distance of 4 m. if he wants to see objects at a distance of 20 m, what should be the focal length and power of the concave lens he must wear?

A person can see clearly only upto a distance of 25 cm . He wants to read a book placed at a distance of 50cm . What kind of lens does he require for his spectacles and what must be its power ?

A person can see clearly only upto a distance of 25 cm . He wants to read a book placed at a distance of 50cm . What kind of lens does he require for his spectacles and what must be its power ?

If a person can sees clearly at a distance of 100 cm, then find the power of leris used to see object at 40 cm.

If a person can sees clearly at a distance of 100 cm, then find the power of leris used to see object at 40 cm.