The focal length of a lens determines the magnification at which it images distant objects. It is equal to the distance between the image plane and a pinhole that images distant objects the same size as the lens in question.hen a lens is used to form an image of some object, the distance from the object to the lens u, the distance from the lens to the image v, and the focal length f are related by. The focal length of a thin lens can be easily measured by using it to form an image of a distant light source on a screen.
The Killing Fields (Khmer: áá¶ááá·áá¶á viel pi-kÊ°iet) are a number of sites in Cambodia where collectively more than a million people were killed and buried by the communist Khmer Rouge regime, during its rule of the country from 1975 to 1979, immediately after the end of the Cambodian Civil War (1970â1975).
to gather the crop from: to harvest the fields. 8. to gain, win, or use (a prize, product, or result of any past act, process, etc.): She has finally harvested the rewards of her dedication.