Assignment:
QUESTION 1
Hyperopia is usually corrected with
A. cylindrical lenses
B. achromatic doublet lenses
C. diverging lenses
D. converging lenses
QUESTION 2
Myopia is usually corrected with
A. cylindrical lenses
B. achromatic doublet lenses
C. diverging lenses
D. converging lenses
QUESTION 3
The far point of a near-sighted person
A. is usually closer than 25 cm from the eye
B. is at infinity
C. is usually farther than 25 cm from the eye but less than infinity
D. is 25 cm from the eye
QUESTION 4
As a person ages, their eyelenses become less and less able to squeeze themselves into the proper shape needed to bring light from nearby sources into a focus on the retina. This occurs because
A. The eyelens changes shape as we age
B. The index of refraction of the eyelens becomes smaller as we age
C. Additional layers form on the eyelens, insulating it from the vitreous humor liquid and making it less flexible
D. The eyelens moves farther into the eye as we age
QUESTION 5
For three people, their eyeglass prescriptions specify the following: +3D, -3D and bifocals. These three people are, respectively
A. Hyperopic, myopic, presbyopic
B. Astigmatic, myopic, presbyopic
C. Myopic, presbyopic, hyperopic
D. None of the above
QUESTION 6
The benefit of using a Schmidt corrector plate in a reflecting telescope is that
A. It bends the incoming parallel rays just enough to correct for the spherical aberration of the primary mirror
B. It covers the top of the telescope tube, keeping dirt and air currents out of the tube
C. Both A and B
D. It brings the rays to a focus
QUESTION 7
An object sits at the focal point of a parabolic mirror. At what distance from the mirror will the image of the object be created?
A. It will be imaged at half its focal length
B. It will be imaged at its focal length
C. It will be imaged at twice its focal length
D. None - the beams will be reflected parallel to each other and no image will be formed
QUESTION 8
Why do reflecting telescopes use curved mirrors instead of flat mirrors?
A. To make converging beams of light become parallel
B. To redirect parallel beams of light to converge to a point
C. Because curved mirrors reflect light in a wavelength-dependent way
D. None of the above
QUESTION 9
The reason why chromatic aberration isn't a problem for reflecting telescopes is that
A. The law of reflection holds for all wavelengths, so blue light and red light are reflected by the same amount
B. The shape of the mirror in a reflector telescope can compensate for the chromatic aberration
C. Only specific wavelengths of light are reflected
D. A and C
QUESTION 10
The more curved a convex lens becomes, the smaller its focal length becomes, and vice versa. What then is the focal length of a flat, plane piece of glass?
A. zero
B. depends on the index of refraction, n, of the glass
C. it's effectively infinite
D. it's very small if illuminated by red light, and very large if illuminated by blue light
QUESTION 11
How does the light-gathering power of an 8-meter telescope compare to a 3-meter telescope?
A. It is about 2.5 times larger
B. It is about 5 times larger
C. It is about 7 times larger
D. It is about 7 times smaller
QUESTION 12
I am nearsighted (myopic), so instead of my far point being infinitely far away, it's ony 80 cm away. How many diopters will my prescription glasses need?
A. -1.25D
B. +1.25D
C. +2.75D
D. none; my vision is fine!
QUESTION 13
The figure shows a schematic diagram of a defective eye and some lenses. Which of the lenses shown can correct for this defect?
A. (biconvex lens)
B. (planar lens)
C. (plano-concave lens)
D. (bi-concave lens)
E. (negative meniscus lens)
QUESTION 14
When the ciliary muscles of the eye remain tensed for a significant period of time, eyestrain results. Which of the following instruments is least related to eye strain?
A. A telescope
B. A microscope
C. A magnifying glass
D. Sunglasses
QUESTION 15
Observatories are usually located on mountaintops because
A. On the mountaintop it's closer to the stars
B. Higher up the air is steadier and drier, and this makes for better seeing of the sky
C. There is less wind on a mountaintop
D. It's usually warmer on mountaintops, making it easier on astronomers
QUESTION 16
I have a refracting telescope with an objective lens focal length f=200 mm. I have three possible eyepieces I can use with this telescope, having focal lengths of 9 mm, 25mm and 50 mm. I want to look at the planet Jupiter though the telescope, and I would like to make out details on the banded clouds encircling the planet (i.e., I'd like to see a highly magnified view). Which eyepiece would I best use for this?
A. 9 mm
B. 25 mm
C. 50 mm
D. It doesn't matter which one
QUESTION 17
Similar to the above question, I have a refracting telescope with an objective lens focal length f=200 mm. I have three possible eyepieces I can use with this telescope, having focal lengths of 9 mm, 25mm and 50 mm. I want to look at a cluster of stars which are well spread apart from each other on the sky. Which eyepiece would I best use for this?
A. 9 mm
B. 25 mm
C. 50 mm
D. It doesn't matter which one
QUESTION 18
By the Rayleigh criterion, if I use a 4-meter telescope, I can make out stars that are ____ as far apart as stars observed through a 2-meter telescope
A. Equally
B. Half
C. Twice
D. None of the above
QUESTION 19
Parallel rays of light are shown entering the lens system in the attached diagram. The two lenses are separated by their combined focal lengths. Which answer best describes the rays after they pass through the second lens?
A. Beam widens (but rays still parallel)
B. Beam narrows (but rays still parallel)
C. Beam is focused
D. Beam diverges
QUESTION 20
Which of these statements best explains why a telescope enables us to see details of a distant object such as the Moon or a planet more clearly?
A. The telescope only lets through shorter wavelengths which are easier for our eye to detect
B. The image formed by the telescope allows us to make out the object in more detail
C. The image formed by the telescope is larger than the object
D. Both B and C: the image is larger and we resolve more detail