2. Diffraction is divergence of light
from its initial straight line of travel.
3. Light is wavelike because of its
diffraction.
4. Waves do not move in straight line
when they are diffracted.
5. Diffraction occurs when wave passed
around sharp edge.
6. Diffraction occur when wave pass
through sharp corners.
7. The two types of diffraction
phenomena are fraunhofer and Fresnel diffraction pattern.
8. Fresnel diffraction pattern is when
the rays reaching the screen are not parallel.
9. In fraunhofer diffraction pattern is
when the rays reaching the screen are almost parallel.
10.
In
fraunhofer diffraction the screen are
placed very far away from the source to converging lens are used to focus on the
image
11.
Rayleigh
criterion is a limiting condition for resolution.
12.
Images
formed by two sources are said to be resolved if their central maxima do not
overlap.
13.
Images
formed by two sources are said to be not resolved if their central maxima overlap
14.
In
Fresnel pattern the screen are placed close the source.
15.
Geometric
shadow was first observed by Francesco Grimaldi in 17th century.
16.
That region which a given type of radiation would not
reach, because of the presence of an object, if the effects of diffraction and
interference could be neglected.(3)
17.
Diffraction grating is a device for analyzing light
source.
18.
condition for
intensity maxima in diffraction grating
is given by dsinθ=mλ, where
19.
Circular
aperture diffraction production of diffuse circular disc of shadow.
20.
Diffuse
circular disc of shadow in circular aperture diffraction is called airy disk.
21.
Diffraction
is more pronounced if the wavelength is equal to the opening.
22.
Diffraction
was 1st observed by Francesco grimaldi in 1660.
23.
particles at atomic levels can also be
diffracted
24.
Diffraction
occurs due to interference of waves as they encounter an obstacle or sharp
edge.
25.
Diffractions
involve two processes, breaking up of waves and reconstruction through
interference.
26.
Diffraction
at atomic levels is studies under quantum mechanics.
27.
Brag
diffraction is diffraction from atoms in crystals.
28.
Rayleigh
criterion states that says that two images formed by an aperture are
distinguishable only if the central maxima of the diffraction pattern for one
image fall on the first minimum of the other image.
29.
Sunlight
is diffracted by water droplets, dust particles and air molecules in the atmosphere.
30.
If
the obstacles opening is larger than the wavelength of the light, the
diffraction is more visible than when the obstacle opening is large than the wavelength.
31.
Diffraction
reveals the geometry of the diffracting object.
32.
Constructive
interference of wave result to more pronounced diffraction.
33.
Destructive
interference result to loss of wave and “diminished
diffraction”.
34.
The
intensity is inversely proportional to
the size of geometry (size of the opening) of the object.
35.
Diffraction
observed from a long distance can be explained by fraunhofer diffraction
equation
36.
Diffraction
observed from a near distance can be explained by Fresnel diffraction equation
37.
A
small object placed in the part of light will result to dark and light fringes.
38.
The
scattering of light by dust particles and water droplets is known as
particulate scattering
39.
Straight line is the shortest distance
travelled by light.
40.
Optical
distance is the product of speed of wave and time taken.
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