true and false- 12
In free space light travels along straight lines at a constant speed of c=3*10^8m/s.
T
When light propagates through transparent media, like air or glass, it travels at a higher speed.
F
At the boundary between two media, the amount of deflection or bending of light rays depends upon the change in frequency.
F
Since the speed of light in all material media is higher than the free space speed, the index of refraction is always less than or equal to one
F
The index of refraction of air differs from the index of refraction of vacuum by a very small amount.
T
A penny placed in a clear glass of water appears to be closer to the surface of the water than it actually is because of refraction.
T
Parallel light rays passing through a concave glass will diverge in such a way that they appear to be originating from a single point some distance f behind
the lens.
F
The power P of a lens is defined as the reciprocal of the object distance.
F
The power P of a lens can be calculated by the equation P(D)=1/d(cm)
F
A lens that converges parallel rays of light to a point 100cm past the lens has a power P=1 D.
v
The magnification of a lens is equal to the ratio of the object distance to the image distance.
F
The negative sign for the magnification signifies that the image is inverted with respect to the object
T
If you observe an object through a diverging lens, the object appears higher and further away.
F
Nearsightedness can be corrected by usung a diverging lens to cause the rays to diverge slightly before entering the eye.
T
The common eye defect known as myopia occurs when the lens has different focal lengths for light rays striking it in different planes
F
In a compound microscope, the objective is a lens of a very short focal length which is placed close to the object to be viewed.
T
The resolution of a compound microscope can be enhanced by using monochromatic blue or violet light sources, which have the longest wavelengths in the visible spectrum.
F
Diverging lenses can be used to form real images of objects.
F
The index of refraction is a dimensionless quantity
T
Suppose a light beam strikes the boundary between two media of different refractive indices. If the index of refraction of the first medium is greater than the
index of refraction of the second medium, then the angle of refraction will be bigger than the angle of incidence.
T
For a given type of boundary there is a certain critical angle, beyond which all the light is refracted from the boundary.
F
When a beam of white light is passed through a prism, it is seperated into colored bandy by reflection in the prism.
F
Infrared and ultraviolet light are above and below the visible frequency range, respectively.
F
Cones are concentrated in the center of the retina in an area called the fovea centralis.
T
Color sensitivity is highest when looking straight at an object, because the light rays from the object fall near the fovea centralis.
T
Fiber-optic bundles transmit light even if they are bent into complicated shapes.
T
If the focal length of the eye lens is too short, the image of a distant object will be formed beyond the retina
F
Rods are much more sensitive to light than cones and are much more numerous
T
When the light intensity is low, vision occurs mainly by stimulation of the rods.
T
When the ciliary muscles are relaxed, the crystalline lens of the eye is held in a strained position and the eye is focused upon a closer object
F