fill the blanks - 12
the bending of light rays at interfaces where the speed of light changes is referred to as ...
refraction
the index of refraction, n, is defined by the expression n=....., where...
c/v; c=speed of light in vacuum; v= speed of light is medium
if parallel light rays strike an ideal convex lens, they will focus to a point at a fixed distance f beyond the lens. The distance f is called .... of the lens
focal lenght
The focusing ability of a lens is evaluated in terms of the reciprocal of the focal lenght. This parameter is called the ....... of the lens.
power
the phenomenon, in which there is no transmitted light at all, just reflected light, is known as .....
reflection
a lens which causes parallel light rays to diverge so that they appear to be coming from a point 50cm behind the lens has a power.....
2 diopters
if the object distance is infinite, then the image distance is exactly equal to....
the focal lenght
the converging lens in a simple microscope produces ...... image of an object
real
diverging lenses do not form ..... images and therefore cannot be used to project an image in a screen
real
when light from an object strikes the eye, it passes throught the cornea, the crystslline lens, and the transparent vitreous humor to form an image on ....
the retina
if the focal lenght of the eye lens is too short, the light rays will focus before the retina, resulting in a blurred image. Thix conditions is referred to as ....... or ......
myopia; nearsightendness
the simple magnifier is sometimes called......
simple microscope
...... objectives are used only at very large magnifications that requires high resolving power
oil immersion
the magnification of the compound microscope is the product of the magnifications of the ..... and.......
M objective; M eyepiece
the increased magnification of an electron microscope is made possible by the shorter.... achieved
wavelengths
...... is an instrument for viewing the retina of the eye
the ophtalmoscope
under conditions of ...... the light from the adjacent optical fibers does not mix. Thus, each fiber transmits informations about the luminosity of a localized object area
total internal reflection
fiber-optic bundles are now often used in ...... and other medical optical instrument
gastroscopes
the index of refraction of the prism varies with the ..... of the light, and therefore different frequencies are bent through different angles
frequency
the retina of the eye contains two types of light-sensitive nerve endings, called .... and ....
rods; cones
the sensitivity of the rod vision is considerably reduced by a deficiency in ...
vitamin A
the different colors of light represent different ..... and consequently different wavelenths of light ,
frequencies
the cones provides...... sensitivity, while the rods provide the greater overall light sensitivity need for .... vision
color; night or dark adapted
the magnifier and..... microscope allow the formation of enlarged images of objects form the eye to view
compound
no change in ... of light is observed if it strikes the boundary between two media at an angle of 90°
direction
the effective position of the eye lens is about ..... cm from the retina in the average human eye
2.2
the .... of the eye lens must be change to produce a focused image on the retina
focal length
the Snell's law states that ..... where...
n2/n1 = sin i/ sin r; n1= index of incidence; n2=index of refraction ; i= incident angle; r= refraction angle
a farsighted person has a difficulty seeing objects which are....
closer nearby
the .... is referred to as photopic vision
light-adapted vision