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9 | 739-742 | In this case, the length of the telescope tube is fo + fe Terrestrial telescopes have, in addition, a pair of inverting lenses to
make the final image erect Refracting telescopes can be used both for
terrestrial and astronomical observations For example, consider
a telescope whose objective has a focal length of 100 cm and the eyepiece
a focal length of 1 cm |
9 | 740-743 | Terrestrial telescopes have, in addition, a pair of inverting lenses to
make the final image erect Refracting telescopes can be used both for
terrestrial and astronomical observations For example, consider
a telescope whose objective has a focal length of 100 cm and the eyepiece
a focal length of 1 cm The magnifying power of this telescope is
m = 100/1 = 100 |
9 | 741-744 | Refracting telescopes can be used both for
terrestrial and astronomical observations For example, consider
a telescope whose objective has a focal length of 100 cm and the eyepiece
a focal length of 1 cm The magnifying power of this telescope is
m = 100/1 = 100 Let us consider a pair of stars of actual separation 1¢ (one minute of
arc) |
9 | 742-745 | For example, consider
a telescope whose objective has a focal length of 100 cm and the eyepiece
a focal length of 1 cm The magnifying power of this telescope is
m = 100/1 = 100 Let us consider a pair of stars of actual separation 1¢ (one minute of
arc) The stars appear as though they are separated by an angle of 100 ×
1¢ = 100¢ =1 |
9 | 743-746 | The magnifying power of this telescope is
m = 100/1 = 100 Let us consider a pair of stars of actual separation 1¢ (one minute of
arc) The stars appear as though they are separated by an angle of 100 ×
1¢ = 100¢ =1 67° |
9 | 744-747 | Let us consider a pair of stars of actual separation 1¢ (one minute of
arc) The stars appear as though they are separated by an angle of 100 ×
1¢ = 100¢ =1 67° The main considerations with an astronomical telescope are its light
gathering power and its resolution or resolving power |
9 | 745-748 | The stars appear as though they are separated by an angle of 100 ×
1¢ = 100¢ =1 67° The main considerations with an astronomical telescope are its light
gathering power and its resolution or resolving power The former clearly
depends on the area of the objective |
9 | 746-749 | 67° The main considerations with an astronomical telescope are its light
gathering power and its resolution or resolving power The former clearly
depends on the area of the objective With larger diameters, fainter objects
can be observed |
9 | 747-750 | The main considerations with an astronomical telescope are its light
gathering power and its resolution or resolving power The former clearly
depends on the area of the objective With larger diameters, fainter objects
can be observed The resolving power, or the ability to observe two objects
distinctly, which are in very nearly the same direction, also depends on
the diameter of the objective |
9 | 748-751 | The former clearly
depends on the area of the objective With larger diameters, fainter objects
can be observed The resolving power, or the ability to observe two objects
distinctly, which are in very nearly the same direction, also depends on
the diameter of the objective So, the desirable aim in optical telescopes is
to make them with objective of large diameter |
9 | 749-752 | With larger diameters, fainter objects
can be observed The resolving power, or the ability to observe two objects
distinctly, which are in very nearly the same direction, also depends on
the diameter of the objective So, the desirable aim in optical telescopes is
to make them with objective of large diameter The largest lens objective
in use has a diameter of 40 inch (~1 |
9 | 750-753 | The resolving power, or the ability to observe two objects
distinctly, which are in very nearly the same direction, also depends on
the diameter of the objective So, the desirable aim in optical telescopes is
to make them with objective of large diameter The largest lens objective
in use has a diameter of 40 inch (~1 02 m) |
9 | 751-754 | So, the desirable aim in optical telescopes is
to make them with objective of large diameter The largest lens objective
in use has a diameter of 40 inch (~1 02 m) It is at the Yerkes Observatory
in Wisconsin, USA |
9 | 752-755 | The largest lens objective
in use has a diameter of 40 inch (~1 02 m) It is at the Yerkes Observatory
in Wisconsin, USA Such big lenses tend to be very heavy and therefore,
difficult to make and support by their edges |
9 | 753-756 | 02 m) It is at the Yerkes Observatory
in Wisconsin, USA Such big lenses tend to be very heavy and therefore,
difficult to make and support by their edges Further, it is rather difficult
and expensive to make such large sized lenses which form images that
are free from any kind of chromatic aberration and distortions |
9 | 754-757 | It is at the Yerkes Observatory
in Wisconsin, USA Such big lenses tend to be very heavy and therefore,
difficult to make and support by their edges Further, it is rather difficult
and expensive to make such large sized lenses which form images that
are free from any kind of chromatic aberration and distortions For these reasons, modern telescopes use a concave mirror rather
than a lens for the objective |
9 | 755-758 | Such big lenses tend to be very heavy and therefore,
difficult to make and support by their edges Further, it is rather difficult
and expensive to make such large sized lenses which form images that
are free from any kind of chromatic aberration and distortions For these reasons, modern telescopes use a concave mirror rather
than a lens for the objective Telescopes with mirror objectives are called
reflecting telescopes |
9 | 756-759 | Further, it is rather difficult
and expensive to make such large sized lenses which form images that
are free from any kind of chromatic aberration and distortions For these reasons, modern telescopes use a concave mirror rather
than a lens for the objective Telescopes with mirror objectives are called
reflecting telescopes There is no chromatic aberration in a mirror |
9 | 757-760 | For these reasons, modern telescopes use a concave mirror rather
than a lens for the objective Telescopes with mirror objectives are called
reflecting telescopes There is no chromatic aberration in a mirror Mechanical support is much less of a problem since a mirror weighs
much less than a lens of equivalent optical quality, and can be supported
over its entire back surface, not just over its rim |
9 | 758-761 | Telescopes with mirror objectives are called
reflecting telescopes There is no chromatic aberration in a mirror Mechanical support is much less of a problem since a mirror weighs
much less than a lens of equivalent optical quality, and can be supported
over its entire back surface, not just over its rim One obvious problem
with a reflecting telescope is that the objective mirror focusses light inside
Rationalised 2023-24
Physics
246
SUMMARY
1 |
9 | 759-762 | There is no chromatic aberration in a mirror Mechanical support is much less of a problem since a mirror weighs
much less than a lens of equivalent optical quality, and can be supported
over its entire back surface, not just over its rim One obvious problem
with a reflecting telescope is that the objective mirror focusses light inside
Rationalised 2023-24
Physics
246
SUMMARY
1 Reflection is governed by the equation Ði = Ðr¢ and refraction by the
Snell’s law, sini/sinr = n, where the incident ray, reflected ray, refracted
ray and normal lie in the same plane |
9 | 760-763 | Mechanical support is much less of a problem since a mirror weighs
much less than a lens of equivalent optical quality, and can be supported
over its entire back surface, not just over its rim One obvious problem
with a reflecting telescope is that the objective mirror focusses light inside
Rationalised 2023-24
Physics
246
SUMMARY
1 Reflection is governed by the equation Ði = Ðr¢ and refraction by the
Snell’s law, sini/sinr = n, where the incident ray, reflected ray, refracted
ray and normal lie in the same plane Angles of incidence, reflection
and refraction are i, r ¢ and r, respectively |
9 | 761-764 | One obvious problem
with a reflecting telescope is that the objective mirror focusses light inside
Rationalised 2023-24
Physics
246
SUMMARY
1 Reflection is governed by the equation Ði = Ðr¢ and refraction by the
Snell’s law, sini/sinr = n, where the incident ray, reflected ray, refracted
ray and normal lie in the same plane Angles of incidence, reflection
and refraction are i, r ¢ and r, respectively 2 |
9 | 762-765 | Reflection is governed by the equation Ði = Ðr¢ and refraction by the
Snell’s law, sini/sinr = n, where the incident ray, reflected ray, refracted
ray and normal lie in the same plane Angles of incidence, reflection
and refraction are i, r ¢ and r, respectively 2 The critical angle of incidence ic for a ray incident from a denser to rarer
medium, is that angle for which the angle of refraction is 90° |
9 | 763-766 | Angles of incidence, reflection
and refraction are i, r ¢ and r, respectively 2 The critical angle of incidence ic for a ray incident from a denser to rarer
medium, is that angle for which the angle of refraction is 90° For
i > ic, total internal reflection occurs |
9 | 764-767 | 2 The critical angle of incidence ic for a ray incident from a denser to rarer
medium, is that angle for which the angle of refraction is 90° For
i > ic, total internal reflection occurs Multiple internal reflections in
diamond (ic @ 24 |
9 | 765-768 | The critical angle of incidence ic for a ray incident from a denser to rarer
medium, is that angle for which the angle of refraction is 90° For
i > ic, total internal reflection occurs Multiple internal reflections in
diamond (ic @ 24 4°), totally reflecting prisms and mirage, are some
examples of total internal reflection |
9 | 766-769 | For
i > ic, total internal reflection occurs Multiple internal reflections in
diamond (ic @ 24 4°), totally reflecting prisms and mirage, are some
examples of total internal reflection Optical fibres consist of glass
fibres coated with a thin layer of material of lower refractive index |
9 | 767-770 | Multiple internal reflections in
diamond (ic @ 24 4°), totally reflecting prisms and mirage, are some
examples of total internal reflection Optical fibres consist of glass
fibres coated with a thin layer of material of lower refractive index Light incident at an angle at one end comes out at the other, after
multiple internal reflections, even if the fibre is bent |
9 | 768-771 | 4°), totally reflecting prisms and mirage, are some
examples of total internal reflection Optical fibres consist of glass
fibres coated with a thin layer of material of lower refractive index Light incident at an angle at one end comes out at the other, after
multiple internal reflections, even if the fibre is bent FIGURE 9 |
9 | 769-772 | Optical fibres consist of glass
fibres coated with a thin layer of material of lower refractive index Light incident at an angle at one end comes out at the other, after
multiple internal reflections, even if the fibre is bent FIGURE 9 26 Schematic diagram of a reflecting telescope (Cassegrain) |
9 | 770-773 | Light incident at an angle at one end comes out at the other, after
multiple internal reflections, even if the fibre is bent FIGURE 9 26 Schematic diagram of a reflecting telescope (Cassegrain) the telescope tube |
9 | 771-774 | FIGURE 9 26 Schematic diagram of a reflecting telescope (Cassegrain) the telescope tube One must have an eyepiece and the observer right
there, obstructing some light (depending on the size of the observer cage) |
9 | 772-775 | 26 Schematic diagram of a reflecting telescope (Cassegrain) the telescope tube One must have an eyepiece and the observer right
there, obstructing some light (depending on the size of the observer cage) This is what is done in the very large 200 inch (~5 |
9 | 773-776 | the telescope tube One must have an eyepiece and the observer right
there, obstructing some light (depending on the size of the observer cage) This is what is done in the very large 200 inch (~5 08 m) diameters, Mt |
9 | 774-777 | One must have an eyepiece and the observer right
there, obstructing some light (depending on the size of the observer cage) This is what is done in the very large 200 inch (~5 08 m) diameters, Mt Palomar telescope, California |
9 | 775-778 | This is what is done in the very large 200 inch (~5 08 m) diameters, Mt Palomar telescope, California The viewer sits near the focal point of the
mirror, in a small cage |
9 | 776-779 | 08 m) diameters, Mt Palomar telescope, California The viewer sits near the focal point of the
mirror, in a small cage Another solution to the problem is to deflect the
light being focussed by another mirror |
9 | 777-780 | Palomar telescope, California The viewer sits near the focal point of the
mirror, in a small cage Another solution to the problem is to deflect the
light being focussed by another mirror One such arrangement using a
convex secondary mirror to focus the incident light, which now passes
through a hole in the objective primary mirror, is shown in Fig |
9 | 778-781 | The viewer sits near the focal point of the
mirror, in a small cage Another solution to the problem is to deflect the
light being focussed by another mirror One such arrangement using a
convex secondary mirror to focus the incident light, which now passes
through a hole in the objective primary mirror, is shown in Fig 9 |
9 | 779-782 | Another solution to the problem is to deflect the
light being focussed by another mirror One such arrangement using a
convex secondary mirror to focus the incident light, which now passes
through a hole in the objective primary mirror, is shown in Fig 9 26 |
9 | 780-783 | One such arrangement using a
convex secondary mirror to focus the incident light, which now passes
through a hole in the objective primary mirror, is shown in Fig 9 26 This is known as a Cassegrain telescope, after its inventor |
9 | 781-784 | 9 26 This is known as a Cassegrain telescope, after its inventor It has the
advantages of a large focal length in a short telescope |
9 | 782-785 | 26 This is known as a Cassegrain telescope, after its inventor It has the
advantages of a large focal length in a short telescope The largest telescope
in India is in Kavalur, Tamil Nadu |
9 | 783-786 | This is known as a Cassegrain telescope, after its inventor It has the
advantages of a large focal length in a short telescope The largest telescope
in India is in Kavalur, Tamil Nadu It is a 2 |
9 | 784-787 | It has the
advantages of a large focal length in a short telescope The largest telescope
in India is in Kavalur, Tamil Nadu It is a 2 34 m diameter reflecting
telescope (Cassegrain) |
9 | 785-788 | The largest telescope
in India is in Kavalur, Tamil Nadu It is a 2 34 m diameter reflecting
telescope (Cassegrain) It was ground, polished, set up, and is being used
by the Indian Institute of Astrophysics, Bangalore |
9 | 786-789 | It is a 2 34 m diameter reflecting
telescope (Cassegrain) It was ground, polished, set up, and is being used
by the Indian Institute of Astrophysics, Bangalore The largest reflecting
telescopes in the world are the pair of Keck telescopes in Hawaii, USA,
with a reflector of 10 metre in diameter |
9 | 787-790 | 34 m diameter reflecting
telescope (Cassegrain) It was ground, polished, set up, and is being used
by the Indian Institute of Astrophysics, Bangalore The largest reflecting
telescopes in the world are the pair of Keck telescopes in Hawaii, USA,
with a reflector of 10 metre in diameter Rationalised 2023-24
Ray Optics and
Optical Instruments
247
3 |
9 | 788-791 | It was ground, polished, set up, and is being used
by the Indian Institute of Astrophysics, Bangalore The largest reflecting
telescopes in the world are the pair of Keck telescopes in Hawaii, USA,
with a reflector of 10 metre in diameter Rationalised 2023-24
Ray Optics and
Optical Instruments
247
3 Cartesian sign convention: Distances measured in the same direction
as the incident light are positive; those measured in the opposite
direction are negative |
9 | 789-792 | The largest reflecting
telescopes in the world are the pair of Keck telescopes in Hawaii, USA,
with a reflector of 10 metre in diameter Rationalised 2023-24
Ray Optics and
Optical Instruments
247
3 Cartesian sign convention: Distances measured in the same direction
as the incident light are positive; those measured in the opposite
direction are negative All distances are measured from the pole/optic
centre of the mirror/lens on the principal axis |
9 | 790-793 | Rationalised 2023-24
Ray Optics and
Optical Instruments
247
3 Cartesian sign convention: Distances measured in the same direction
as the incident light are positive; those measured in the opposite
direction are negative All distances are measured from the pole/optic
centre of the mirror/lens on the principal axis The heights measured
upwards above x-axis and normal to the principal axis of the mirror/
lens are taken as positive |
9 | 791-794 | Cartesian sign convention: Distances measured in the same direction
as the incident light are positive; those measured in the opposite
direction are negative All distances are measured from the pole/optic
centre of the mirror/lens on the principal axis The heights measured
upwards above x-axis and normal to the principal axis of the mirror/
lens are taken as positive The heights measured downwards are taken
as negative |
9 | 792-795 | All distances are measured from the pole/optic
centre of the mirror/lens on the principal axis The heights measured
upwards above x-axis and normal to the principal axis of the mirror/
lens are taken as positive The heights measured downwards are taken
as negative 4 |
9 | 793-796 | The heights measured
upwards above x-axis and normal to the principal axis of the mirror/
lens are taken as positive The heights measured downwards are taken
as negative 4 Mirror equation:
1
1
1
v
u
f
+
=
where u and v are object and image distances, respectively and f is the
focal length of the mirror |
9 | 794-797 | The heights measured downwards are taken
as negative 4 Mirror equation:
1
1
1
v
u
f
+
=
where u and v are object and image distances, respectively and f is the
focal length of the mirror f is (approximately) half the radius of
curvature R |
9 | 795-798 | 4 Mirror equation:
1
1
1
v
u
f
+
=
where u and v are object and image distances, respectively and f is the
focal length of the mirror f is (approximately) half the radius of
curvature R f is negative for concave mirror; f is positive for a convex
mirror |
9 | 796-799 | Mirror equation:
1
1
1
v
u
f
+
=
where u and v are object and image distances, respectively and f is the
focal length of the mirror f is (approximately) half the radius of
curvature R f is negative for concave mirror; f is positive for a convex
mirror 5 |
9 | 797-800 | f is (approximately) half the radius of
curvature R f is negative for concave mirror; f is positive for a convex
mirror 5 For a prism of the angle A, of refractive index n 2 placed in a medium
of refractive index n1,
n
n
n
A
D
A
m
21
2
1
2
2
=
=
+
(
)
(
)
sin
/
sin
/
where Dm is the angle of minimum deviation |
9 | 798-801 | f is negative for concave mirror; f is positive for a convex
mirror 5 For a prism of the angle A, of refractive index n 2 placed in a medium
of refractive index n1,
n
n
n
A
D
A
m
21
2
1
2
2
=
=
+
(
)
(
)
sin
/
sin
/
where Dm is the angle of minimum deviation 6 |
9 | 799-802 | 5 For a prism of the angle A, of refractive index n 2 placed in a medium
of refractive index n1,
n
n
n
A
D
A
m
21
2
1
2
2
=
=
+
(
)
(
)
sin
/
sin
/
where Dm is the angle of minimum deviation 6 For refraction through a spherical interface (from medium 1 to 2 of
refractive index n1 and n 2, respectively)
2
1
2
1
n
n
n
n
v
u
−R
−
=
Thin lens formula
1
1
1
v
u
f
−
=
Lens maker’s formula
1
1
1
2
1
1
1
2
f
n
n
n
R
R
=
−
(
)
−
R1 and R2 are the radii of curvature of the lens surfaces |
9 | 800-803 | For a prism of the angle A, of refractive index n 2 placed in a medium
of refractive index n1,
n
n
n
A
D
A
m
21
2
1
2
2
=
=
+
(
)
(
)
sin
/
sin
/
where Dm is the angle of minimum deviation 6 For refraction through a spherical interface (from medium 1 to 2 of
refractive index n1 and n 2, respectively)
2
1
2
1
n
n
n
n
v
u
−R
−
=
Thin lens formula
1
1
1
v
u
f
−
=
Lens maker’s formula
1
1
1
2
1
1
1
2
f
n
n
n
R
R
=
−
(
)
−
R1 and R2 are the radii of curvature of the lens surfaces f is positive
for a converging lens; f is negative for a diverging lens |
9 | 801-804 | 6 For refraction through a spherical interface (from medium 1 to 2 of
refractive index n1 and n 2, respectively)
2
1
2
1
n
n
n
n
v
u
−R
−
=
Thin lens formula
1
1
1
v
u
f
−
=
Lens maker’s formula
1
1
1
2
1
1
1
2
f
n
n
n
R
R
=
−
(
)
−
R1 and R2 are the radii of curvature of the lens surfaces f is positive
for a converging lens; f is negative for a diverging lens The power of a
lens P = 1/f |
9 | 802-805 | For refraction through a spherical interface (from medium 1 to 2 of
refractive index n1 and n 2, respectively)
2
1
2
1
n
n
n
n
v
u
−R
−
=
Thin lens formula
1
1
1
v
u
f
−
=
Lens maker’s formula
1
1
1
2
1
1
1
2
f
n
n
n
R
R
=
−
(
)
−
R1 and R2 are the radii of curvature of the lens surfaces f is positive
for a converging lens; f is negative for a diverging lens The power of a
lens P = 1/f The SI unit for power of a lens is dioptre (D): 1 D = 1 m–1 |
9 | 803-806 | f is positive
for a converging lens; f is negative for a diverging lens The power of a
lens P = 1/f The SI unit for power of a lens is dioptre (D): 1 D = 1 m–1 If several thin lenses of focal length f1, f2, f3, |
9 | 804-807 | The power of a
lens P = 1/f The SI unit for power of a lens is dioptre (D): 1 D = 1 m–1 If several thin lenses of focal length f1, f2, f3, are in contact, the
effective focal length of their combination, is given by
1
2
3
1
1
1
1
f
f
f
f
=
+
+
+ …
The total power of a combination of several lenses is
P = P1 + P2 + P3 + …
7 |
9 | 805-808 | The SI unit for power of a lens is dioptre (D): 1 D = 1 m–1 If several thin lenses of focal length f1, f2, f3, are in contact, the
effective focal length of their combination, is given by
1
2
3
1
1
1
1
f
f
f
f
=
+
+
+ …
The total power of a combination of several lenses is
P = P1 + P2 + P3 + …
7 Dispersion is the splitting of light into its constituent colour |
9 | 806-809 | If several thin lenses of focal length f1, f2, f3, are in contact, the
effective focal length of their combination, is given by
1
2
3
1
1
1
1
f
f
f
f
=
+
+
+ …
The total power of a combination of several lenses is
P = P1 + P2 + P3 + …
7 Dispersion is the splitting of light into its constituent colour Rationalised 2023-24
Physics
248
POINTS TO PONDER
1 |
9 | 807-810 | are in contact, the
effective focal length of their combination, is given by
1
2
3
1
1
1
1
f
f
f
f
=
+
+
+ …
The total power of a combination of several lenses is
P = P1 + P2 + P3 + …
7 Dispersion is the splitting of light into its constituent colour Rationalised 2023-24
Physics
248
POINTS TO PONDER
1 The laws of reflection and refraction are true for all surfaces and
pairs of media at the point of the incidence |
9 | 808-811 | Dispersion is the splitting of light into its constituent colour Rationalised 2023-24
Physics
248
POINTS TO PONDER
1 The laws of reflection and refraction are true for all surfaces and
pairs of media at the point of the incidence 2 |
9 | 809-812 | Rationalised 2023-24
Physics
248
POINTS TO PONDER
1 The laws of reflection and refraction are true for all surfaces and
pairs of media at the point of the incidence 2 The real image of an object placed between f and 2f from a convex lens
can be seen on a screen placed at the image location |
9 | 810-813 | The laws of reflection and refraction are true for all surfaces and
pairs of media at the point of the incidence 2 The real image of an object placed between f and 2f from a convex lens
can be seen on a screen placed at the image location If the screen is
removed, is the image still there |
9 | 811-814 | 2 The real image of an object placed between f and 2f from a convex lens
can be seen on a screen placed at the image location If the screen is
removed, is the image still there This question puzzles many, because
it is difficult to reconcile ourselves with an image suspended in air
without a screen |
9 | 812-815 | The real image of an object placed between f and 2f from a convex lens
can be seen on a screen placed at the image location If the screen is
removed, is the image still there This question puzzles many, because
it is difficult to reconcile ourselves with an image suspended in air
without a screen But the image does exist |
9 | 813-816 | If the screen is
removed, is the image still there This question puzzles many, because
it is difficult to reconcile ourselves with an image suspended in air
without a screen But the image does exist Rays from a given point
on the object are converging to an image point in space and diverging
away |
9 | 814-817 | This question puzzles many, because
it is difficult to reconcile ourselves with an image suspended in air
without a screen But the image does exist Rays from a given point
on the object are converging to an image point in space and diverging
away The screen simply diffuses these rays, some of which reach our
eye and we see the image |
9 | 815-818 | But the image does exist Rays from a given point
on the object are converging to an image point in space and diverging
away The screen simply diffuses these rays, some of which reach our
eye and we see the image This can be seen by the images formed in
air during a laser show |
9 | 816-819 | Rays from a given point
on the object are converging to an image point in space and diverging
away The screen simply diffuses these rays, some of which reach our
eye and we see the image This can be seen by the images formed in
air during a laser show 3 |
9 | 817-820 | The screen simply diffuses these rays, some of which reach our
eye and we see the image This can be seen by the images formed in
air during a laser show 3 Image formation needs regular reflection/refraction |
9 | 818-821 | This can be seen by the images formed in
air during a laser show 3 Image formation needs regular reflection/refraction In principle, all
rays from a given point should reach the same image point |
9 | 819-822 | 3 Image formation needs regular reflection/refraction In principle, all
rays from a given point should reach the same image point This is
why you do not see your image by an irregular reflecting object, say
the page of a book |
9 | 820-823 | Image formation needs regular reflection/refraction In principle, all
rays from a given point should reach the same image point This is
why you do not see your image by an irregular reflecting object, say
the page of a book 4 |
9 | 821-824 | In principle, all
rays from a given point should reach the same image point This is
why you do not see your image by an irregular reflecting object, say
the page of a book 4 Thick lenses give coloured images due to dispersion |
9 | 822-825 | This is
why you do not see your image by an irregular reflecting object, say
the page of a book 4 Thick lenses give coloured images due to dispersion The variety in
colour of objects we see around us is due to the constituent colours
of the light incident on them |
9 | 823-826 | 4 Thick lenses give coloured images due to dispersion The variety in
colour of objects we see around us is due to the constituent colours
of the light incident on them A monochromatic light may produce an
entirely different perception about the colours on an object as seen in
white light |
9 | 824-827 | Thick lenses give coloured images due to dispersion The variety in
colour of objects we see around us is due to the constituent colours
of the light incident on them A monochromatic light may produce an
entirely different perception about the colours on an object as seen in
white light 5 |
9 | 825-828 | The variety in
colour of objects we see around us is due to the constituent colours
of the light incident on them A monochromatic light may produce an
entirely different perception about the colours on an object as seen in
white light 5 For a simple microscope, the angular size of the object equals the
angular size of the image |
9 | 826-829 | A monochromatic light may produce an
entirely different perception about the colours on an object as seen in
white light 5 For a simple microscope, the angular size of the object equals the
angular size of the image Yet it offers magnification because we can
keep the small object much closer to the eye than 25 cm and hence
have it subtend a large angle |
9 | 827-830 | 5 For a simple microscope, the angular size of the object equals the
angular size of the image Yet it offers magnification because we can
keep the small object much closer to the eye than 25 cm and hence
have it subtend a large angle The image is at 25 cm which we can see |
9 | 828-831 | For a simple microscope, the angular size of the object equals the
angular size of the image Yet it offers magnification because we can
keep the small object much closer to the eye than 25 cm and hence
have it subtend a large angle The image is at 25 cm which we can see Without the microscope, you would need to keep the small object at
25 cm which would subtend a very small angle |
9 | 829-832 | Yet it offers magnification because we can
keep the small object much closer to the eye than 25 cm and hence
have it subtend a large angle The image is at 25 cm which we can see Without the microscope, you would need to keep the small object at
25 cm which would subtend a very small angle 8 |
9 | 830-833 | The image is at 25 cm which we can see Without the microscope, you would need to keep the small object at
25 cm which would subtend a very small angle 8 Magnifying power m of a simple microscope is given by m = 1 + (D/f),
where D = 25 cm is the least distance of distinct vision and f is the
focal length of the convex lens |
9 | 831-834 | Without the microscope, you would need to keep the small object at
25 cm which would subtend a very small angle 8 Magnifying power m of a simple microscope is given by m = 1 + (D/f),
where D = 25 cm is the least distance of distinct vision and f is the
focal length of the convex lens If the image is at infinity, m = D/f |
9 | 832-835 | 8 Magnifying power m of a simple microscope is given by m = 1 + (D/f),
where D = 25 cm is the least distance of distinct vision and f is the
focal length of the convex lens If the image is at infinity, m = D/f For
a compound microscope, the magnifying power is given by m = me × m0
where me = 1 + (D/fe), is the magnification due to the eyepiece and mo
is the magnification produced by the objective |
9 | 833-836 | Magnifying power m of a simple microscope is given by m = 1 + (D/f),
where D = 25 cm is the least distance of distinct vision and f is the
focal length of the convex lens If the image is at infinity, m = D/f For
a compound microscope, the magnifying power is given by m = me × m0
where me = 1 + (D/fe), is the magnification due to the eyepiece and mo
is the magnification produced by the objective Approximately,
o
e
L
D
m
f
f
=
×
where fo and fe are the focal lengths of the objective and eyepiece,
respectively, and L is the distance between their focal points |
9 | 834-837 | If the image is at infinity, m = D/f For
a compound microscope, the magnifying power is given by m = me × m0
where me = 1 + (D/fe), is the magnification due to the eyepiece and mo
is the magnification produced by the objective Approximately,
o
e
L
D
m
f
f
=
×
where fo and fe are the focal lengths of the objective and eyepiece,
respectively, and L is the distance between their focal points 9 |
9 | 835-838 | For
a compound microscope, the magnifying power is given by m = me × m0
where me = 1 + (D/fe), is the magnification due to the eyepiece and mo
is the magnification produced by the objective Approximately,
o
e
L
D
m
f
f
=
×
where fo and fe are the focal lengths of the objective and eyepiece,
respectively, and L is the distance between their focal points 9 Magnifying power m of a telescope is the ratio of the angle b subtended
at the eye by the image to the angle a subtended at the eye by the
object |
9 | 836-839 | Approximately,
o
e
L
D
m
f
f
=
×
where fo and fe are the focal lengths of the objective and eyepiece,
respectively, and L is the distance between their focal points 9 Magnifying power m of a telescope is the ratio of the angle b subtended
at the eye by the image to the angle a subtended at the eye by the
object o
e
f
m
f
=αβ
=
where f0 and fe are the focal lengths of the objective and eyepiece,
respectively |
9 | 837-840 | 9 Magnifying power m of a telescope is the ratio of the angle b subtended
at the eye by the image to the angle a subtended at the eye by the
object o
e
f
m
f
=αβ
=
where f0 and fe are the focal lengths of the objective and eyepiece,
respectively Rationalised 2023-24
Ray Optics and
Optical Instruments
249
EXERCISES
9 |
9 | 838-841 | Magnifying power m of a telescope is the ratio of the angle b subtended
at the eye by the image to the angle a subtended at the eye by the
object o
e
f
m
f
=αβ
=
where f0 and fe are the focal lengths of the objective and eyepiece,
respectively Rationalised 2023-24
Ray Optics and
Optical Instruments
249
EXERCISES
9 1
A small candle, 2 |
Subsets and Splits
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