Optical Instruments

The part of the eye that acts as a screen where the image forms is the ...

Nearsightedness (myopia) is corrected using a ... lens.

Farsightedness (hypermetropia) is corrected using a ... lens.

A magnifying glass uses a single ... lens.

The image formed by a camera lens is ...

The near point (punctum proximum) of a normal eye is ...

A lens has a focal length of $50\text{cm}$. Its power is ...

A nearsighted person has a far point of $50\text{cm}$. The power of the needed lens is ...

A farsighted person has a near point of $50\text{cm}$ and wants to read at $25\text{cm}$. The needed lens power is ...

A magnifying glass of focal length $5\text{cm}$ is used with a relaxed eye (near point $25\text{cm}$). Its magnification is ...

A microscope is composed of ...

A telescope has an objective lens of focal length $100\text{cm}$ and an eyepiece of focal length $5\text{cm}$. Its magnification is ...

The unit of lens power is the ...

The ability of the eye lens to change its focal length so objects at various distances are seen clearly is called ...

A nearsighted person has a far point of $40\text{cm}$. The power of the needed lens is ...

A magnifying glass of focal length $10\text{cm}$ is used with maximum accommodation (near point $25\text{cm}$). Its magnification is ...

An astronomical telescope has an objective of focal length $100\text{cm}$ and an eyepiece of focal length $5\text{cm}$. Its length for a relaxed eye is ...

A farsighted person has a near point of $100\text{cm}$. The lens power needed to read at $25\text{cm}$ is ...

A microscope has an objective magnification of $10\times$ and an eyepiece magnification of $5\times$. Its total magnification is ...

A camera has a lens of power $+20\text{diopters}$. When photographing a very distant object, the image forms at a distance of ...