JEE Questions for Physics Ray Optics Quiz 27 - MCQExams.com

A person\'s near point is 50 cm and his far point is 3 m. Power of the lenses he requires for (i) reading and (ii) for seeing distant stars are
  • –2 D and 0.33 D
  • 2 D and –0.33 D
  • –2 D and 3 D
  • 2 D and –3 D
A satisfactory photographic print is obtained when the exposure time is 10 s at a distance of 2 m from a 60 cd lamp. The time of exposure required for the same quality print at a distance of 4 m from a 120 cd lamp is
  • 5 s
  • 10 s
  • 15 s
  • 20 s
A person cannot see objects clearly beyond 2.0 m. The power of lens required to correct his vision will be
  • +2.0 D
  • –1.0 D
  • + 1.0 D
  • –0.5 D
The resolving limit of healthy eye is about

  • Physics-Ray Optics-87029.png
  • 2)
    Physics-Ray Optics-87030.png

  • Physics-Ray Optics-87031.png

  • Physics-Ray Optics-87032.png
When objects at different distances are seen by the eye, which of the following remains constant
  • The focal length of the eye lens
  • The object distance from the eye lens
  • The radii of curvature of the eye lens
  • The image distance from the eye lens
An eye specialist prescribes spectacles having a combination of convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. The power of this lens combination in dioptres is
  • + 1.5
  • –1.5
  • +6.67
  • –6.67
Match the List I with the List II from the combinations shown
Physics-Ray Optics-87035.png
  • I–A; II–C; III–B; IV–D
  • I–B; II–D; III–C; N–A
  • I–D; II–B; III–A; N–C
  • I–D; II–A; III–C; N–B
Two parallel pillars are 11 km away from an observer. The minimum distance between the pillars so that they can be seen separately will be
  • 3.2 m
  • 20.8 m
  • 91.5 m
  • 183 m
Retina of eye acts like …… of camera.
  • Shutter
  • Film
  • Lens
  • None of these
The hyper-metropia is a
  • Short-side defect
  • Long- side defect
  • Bad vision due to old age
  • None of the above
Angular resolving power of human eye is
  • 3.6 × 103
  • 3.6 × 102
  • 3.6 × 104
  • 3.6 × 106
In a compound microscope, the focal lengths of two lenses are 1.5 cm and 6.25 cm. An object is placed at 2 cm form objective and the final image is formed at 25 cm from eye lens. The distance between the two lenses is
  • 6.00 cm
  • 7.75 cm
  • 9.25 cm
  • 11.00 cm
A wire mesh consisting of very small squares is viewed at a distance of 8 cm through a magnifying converging lens of focal length 10 cm, kept close to the eye. The magnification produced by the lens is
  • 5
  • 8
  • 10
  • 20
The magnifying power of a simple microscope is 6. The focal length of its lens in metres will be, if least distance of distinct vision is 25 cm
  • 0.05
  • 0.06
  • 0.25
  • 0.12
A compound microscope has two lenses. The magnifying power of one is 5 and the combined magnifying power is 100. The magnifying power of the other lens is
  • 10
  • 20
  • 50
  • 25
A telescope has an objective lens of focal length 200 cm and an eye piece with focal length 2 cm. If this telescope is used to see a 50 meter tall building at a distance of 2 km, what is the height of the image of the building formed by the objective lens?
  • 5 cm
  • 10 cm
  • 1 cm
  • 2 cm
If F0 and Fe are the focal length of the objective and eyepiece respectively of a telescope, then its magnifying power will be

  • Physics-Ray Optics-87059.png
  • 2)
    Physics-Ray Optics-87060.png

  • Physics-Ray Optics-87061.png

  • Physics-Ray Optics-87062.png
An astronomical telescope has objective and eyepiece lens of powers 0.5 D and 20 D respectively, its magnifying power will be
  • 8
  • 20
  • 30
  • 40
The diameter of the objective of the telescope is 0.1 metre and wavelength of light is 6000 Å. Its resolving power would be approximately
  • 7.32 × 10–6 rad
  • 1.36 × 106 rad
  • 7.32 × 10–5 rad
  • 1.36 × 105 rad
For a telescope to have large resolving power the
  • Focal length of its objective should be large
  • Focal length of its eye piece should be large
  • Focal length of its eye piece should be small
  • Aperture of its objective should be large
The resolving power of an astronomical telescope is 0.2 seconds. If the central half portion of the objective lens is covered, the resolving power will be
  • 0.1 sec
  • 0.2 sec
  • 1.0 sec
  • 0.6 sec
The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 Å is of the order
  • 106 rad
  • 10–2 rad
  • 10–4 rad
  • 10–6 rad
For a compound microscope, the focal lengths of object lens and eye lens are f0 and fe respectively, then magnification will be done by microscope when
  • f0 = fe
  • f0>fe
  • f0e
  • None of these
In a compound microscope the objective of f0 and eyepiece of fe are placed at distance L such that L equals
  • f0 + fe
  • f0– fe
  • Much greater than f0 or fe
  • Much less than f0 or fe
  • Need not depend either value of focal lengths
In a simple microscope, if the final image is located atinfinity then its magnifying power is

  • Physics-Ray Optics-87071.png
  • 2)
    Physics-Ray Optics-87072.png

  • Physics-Ray Optics-87073.png

  • Physics-Ray Optics-87074.png
An astronomical telescope has an angular magnification of magnitude 5 for distant objects. The separation between the objective and the eye piece is 36 cm and the final image is formed at infinity. The focal length f0of the objective and the focal length fe of the eye piece are
  • f0 = 45 cm and fe = - 9 cm
  • f0 = 7.2 cm and fe = 5 cm
  • f0 = 50 cm and fe = 10 cm
  • f0 = 30 cm and fe = 6 cm
In Gallilean telescope, if the powers of an objective and eye lens are respectively +1.25 D and – 20 D, then for relaxed vision, the length and magnification will be
  • 21.25 cm and 16
  • 75 cm and 20
  • 75 cm and 16
  • 8.5 cm and 21.25
An astronomical telescope has a magnifying power 10. The focal length of eyepiece is 20 cm. The focal length of objective is
  • 2 cm
  • 200 cm
  • 1/2 cm
  • 1/200 cm
An opera glass (Gallilean telescope) measures 9 cm from the objective to the eyepiece. The focal length of the objective is 15 cm. Its magnifying power is
  • 2.5
  • 2/5
  • 5/3
  • 0.4
In a laboratory four convex lenses L1, L2, L3 and L4 of focal lengths 2, 4, 6 and 8 cm respectively are available. Two of these lenses form a telescope of length 10 cm and magnifying power 4. The objective and eye lenses are
  • L2, L3
  • L1, L4
  • L3, L2
  • L4, L1
Four lenses of focal length + 15 cm, + 20 cm, + 150cm and + 250 cm are available for making an astronomical telescope. To produce the largest magnification, the focal length of the eye piece should be
  • +15 cm
  • +20 cm
  • +150 cm
  • +250 cm
Large aperture of telescope are used for
  • Large image
  • Greater resolution
  • Reducing lens aberration
  • Ease of manufacture
Two convex lenses of focal lengths 0.3 m and 0.05 m are used to make a telescope. The distance kept between the two is
  • 0.35 m
  • 0.25 m
  • 0.175 m
  • 0.15 m
A Gallilean telescope has objective and eyepiece of focal lengths 200 cm and 2 cm respectively. The magnifying power of the telescope for normal vision is
  • 90
  • 100
  • 108
  • 198
The focal lengths of the objective and eye lenses of a telescope are respectively 200 cm and 5 cm. The maximum magnifying power of the telescope will be
  • –40
  • –48
  • –60
  • –100
If tube length of astronomical telescope is 105 cm and magnifying power is 20 for normal setting, calculate the focal length of objective
  • 100 cm
  • 10 cm
  • 20 cm
  • 25 cm
The focal lengths of the objective and eyepiece of a telescope are respectively 100 cm and 2 cm. The moon subtends an angle of 0.5° at the eye. If it is looked through the telescope, the angle subtended by the moon\'s image will be
  • 100°
  • 50°
  • 25°
  • 10°
The diameter of the objective of a telescope is a, its magnifying power is m and wavelength of light is λ. The resolving power of the telescope is
  • (1.22 λ )/a
  • (1.22a) / λ
  • λm / (1.22a)
  • a / (1.22λ)
The magnifying power of a telescope is 9. When it is adjusted for parallel rays the distance between the objective and eyepiece is 20 cm. The focal length of lenses are
  • 10 cm, 10 cm
  • 15 cm, 5 cm
  • 18 cm, 2 cm
  • 11cm, 9 cm
A movie projector forms an image 3.5m long of an object 35 mm. Supposing there is negligible absorption of light by aperture then illuminance on slide and screen will be in the ratio of
  • 100: 1
  • 104 : 1
  • 1 : 100
  • 1 : 104
\ Lux\ is a unit of
  • Luminous intensity of a source
  • Illuminance on a surface
  • Transmission coefficient of a surface
  • Luminous efficiency of source of light
Total flux produced by a source of 1 cd is
  • 1/4 π
  • 8π
  • 4π
  • 1/8 π
1% of light of a source with luminous intensity 50 candela is incident on a circular surface of radius 10 cm. The average illuminance of surface is
  • 100 lux
  • 200 lux
  • 300 lux
  • 400 lux
A screen receives 3 watt of radiant flux of wavelength 6000 Å. One lumen is equivalent to 1.5 × 10–3watt ofmonochromatic light of wavelength 5550 Å. If relative luminosity for 6000 Å is 0.685 while that for 5550 Å is 1.00, then the luminous flux of the source is
  • 4 × 103 lm
  • 3 × 103 lm
  • 2 × 103 lm
  • 1.37 × 103 m
Short linear object of length 1 lies along the axis of a concave mirror of focal length 1 at a distance u from the pole of the mirror. The size of the image is approximately equal to

  • Physics-Ray Optics-87130.png
  • 2)
    Physics-Ray Optics-87131.png

  • Physics-Ray Optics-87132.png

  • Physics-Ray Optics-87133.png
A thin rod of length f/3 lies along the axis of a concave mirror of focal length f. One end of its magnified image touches an end of the rod. The length of the image is
  • f
  • 1/2 f
  • 2f
  • 1/4 f
Light enters at an angle of incidence in a transparent rod of refractive index n. For what value of the refractive index of the material of the rod the light once entered into it will not leave it through its lateral face what soever be the value of angle of incidence

  • Physics-Ray Optics-87137.png
  • 2)
    Physics-Ray Optics-87138.png

  • Physics-Ray Optics-87139.png

  • Physics-Ray Optics-87140.png
A glass hemisphere of radius 0.04 m and RI. of the material 1.6 is placed centrally over a cross mark on a paper (i) with the flat face; (ii) with the curved face in contact with the paper. In each case the cross mark is viewed directly from above. The position of the images will be
  • (i) 0.04 m from the flat face; (ii) 0.025 m from the flat face
  • (i) At the same position of the cross mark; (ii) 0.025 m below the flat face
  • (i) 0.025 m from the flat face; (ii) 0.04 m from the flat face
  • For both (i) and (ii) 0.025 m from the highest point of the hemisphere
An air bubble in sphere having 4 cm diameter appears 1 cm from surface nearest to eye when looked along diameter. If aµg = 1.5, the distance of bubble from refracting surface is
  • 1.2 cm
  • 3.2 cm
  • 2.8 cm
  • 1.6 cm
A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with the distance d between them. If a parallel beam of light falling on Aleaves B as a parallel beam, then distance d in cm will be
  • 25
  • 15
  • 30
  • 50
0:0:1


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