| Date | November 2016 | Marks available | 1 | Reference code | 16N.3.SL.TZ0.13 |
| Level | Standard level | Paper | Paper 3 | Time zone | 0 - no time zone |
| Command term | Explain | Question number | 13 | Adapted from | N/A |
Question
Both optical refracting telescopes and compound microscopes consist of two converging lenses.
Compare the focal lengths needed for the objective lens in an refracting telescope and in a compound microscope.
A student has four converging lenses of focal length 5, 20, 150 and 500 mm. Determine the maximum magnification that can be obtained with a refracting telescope using two of the lenses.
There are optical telescopes which have diameters about 10 m. There are radio telescopes with single dishes of diameters at least 10 times greater.
(i) Discuss why, for the same number of incident photons per unit area, radio telescopes need to be much larger than optical telescopes.
(ii) Outline how is it possible for radio telescopes to achieve diameters of the order of a thousand kilometres.
The diagram shows a schematic view of a compound microscope with the focal points fo of the objective lens and the focal points fe of the eyepiece lens marked on the axis.
On the diagram, identify with an X, a suitable position for the image formed by the objective of the compound microscope.
Image 1 shows details on the petals of a flower under visible light. Image 2 shows the same flower under ultraviolet light. The magnification is the same, but the resolution is higher in Image 2.
Explain why an ultraviolet microscope can increase the resolution of a compound microscope.
Markscheme
fOBJECTIVE for telescope > fOBJECTIVE for microscope
OR
fOBJECTIVE for telescope> fEYEPIECE for telescope but fOBJECTIVE for microscope< fEYEPIECE for microscope
OR
100 times
i
RF photons have smaller energy, so signal requires larger dish
RF waves have greater wavelength, good resolution requires larger dish
Must see both, reason and explanation.
ii
use of an array of dishes/many mutually connected antennas «so the effective diameter equals to the distance between the furthest antennas»
between fe and eyepiece lens, on its left
Accept any clear indication of the image (eg: X, arrow, dot).
Accept positions which are slightly off axis.
resolution improves as wavelength decreases AND wavelength of UV is smaller
OR
gives resolution formula AND adds that λ is smaller for UV
Examiners report
Syllabus sections
- 17N.3.SL.TZ0.10d: The Hubble Space reflecting telescope has a Cassegrain mounting. Outline the main optical...
- 17N.3.SL.TZ0.10a: Complete the diagram, with a Newtonian mounting, continuing the two rays to show how they...
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17M.3.SL.TZ1.7b.i:
Explain why, for the final image to form at infinity, the distance between the lenses must be 87.5 cm.
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17M.3.SL.TZ1.7c:
By reference to chromatic aberration, explain one advantage of a reflecting telescope over a refracting telescope.
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16N.3.SL.TZ0.13c:
There are optical telescopes which have diameters about 10 m. There are radio telescopes with single dishes of diameters at least 10 times greater.
(i) Discuss why, for the same number of incident photons per unit area, radio telescopes need to be much larger than optical telescopes.
(ii) Outline how is it possible for radio telescopes to achieve diameters of the order of a thousand kilometres.
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17M.3.SL.TZ2.9c:
State two advantages of the use of satellite-borne telescopes compared to Earth-based telescopes.
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18M.3.SL.TZ2.9b:
This arrangement using the secondary mirror is said to increase the focal length of the primary mirror. State why this is an advantage.
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16N.3.SL.TZ0.13d:
The diagram shows a schematic view of a compound microscope with the focal points fo of the objective lens and the focal points fe of the eyepiece lens marked on the axis.
On the diagram, identify with an X, a suitable position for the image formed by the objective of the compound microscope.
- 18N.3.SL.TZ0.9a: Draw rays on the diagram to show the formation of the final image.
- 16N.3.SL.TZ0.13a: Compare the focal lengths needed for the objective lens in an refracting telescope and in a...
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16N.3.SL.TZ0.13b:
A student has four converging lenses of focal length 5, 20, 150 and 500 mm. Determine the maximum magnification that can be obtained with a refracting telescope using two of the lenses.
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19M.3.SL.TZ2.11biii:
A new object is placed a few meters to the left of the original lens. The student adjusts spacing of the lenses to form a virtual image at infinity of the new object. Outline, without calculation, the required change to the lens separation.
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17M.3.SL.TZ1.7b.ii:
The angular diameter of the Moon at the naked eye is 7.8 × 10–3 rad.
Calculate the angular diameter of the final image of the Moon.
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19N.3.SL.TZ0.8b:
Calculate, in cm, the distance between the eyepiece and the image formed by the objective lens.
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17N.3.SL.TZ0.10b:
When the Earth-Moon distance is 363 300 km, the Moon is observed using the telescope. The mean radius of the Moon is 1737 km. Determine the focal length of the mirror used in this telescope when the diameter of the Moon’s image formed by the main mirror is 1.20 cm.
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18M.3.HL.TZ2.13c:
It is proposed to build an array of radio telescopes such that the maximum distance between them is 3800 km. The array will operate at a wavelength of 2.1 cm.
Comment on whether it is possible to build an optical telescope operating at 580 nm that is to have the same resolution as the array.
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18N.3.SL.TZ0.9b.ii:
Determine the magnification of the microscope.
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18M.3.SL.TZ2.9c:
Distinguish between this mounting and the Newtonian mounting.
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19M.3.SL.TZ2.11bii:
The image at I is the object for a second converging lens. This second lens forms a final image at infinity with an overall angular magnification for the two lens arrangement of 5. Calculate the distance between the two converging lenses.
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19N.3.SL.TZ0.8c:
Determine, in cm, the focal length of the objective lens.
- 20N.3.SL.TZ0.12b: Sketch a ray diagram to find the position of the images for both lenses in the compound...
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20N.3.SL.TZ0.12a:
Outline the meaning of normal adjustment for a compound microscope.
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17M.3.SL.TZ2.9a:
Determine the focal length of each lens.
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17M.3.SL.TZ2.9b:
The telescope is used to form an image of the Moon. The angle subtended by the image of the Moon at the eyepiece is 0.16 rad. The distance to the Moon is 3.8 x 108 m. Estimate the diameter of the Moon.
