ASSIGNMENT 4: QUESTIONS AND CORRECT DETAILED ANSWERS (VERIFIED
ANSWERS) | ASSURED SUCCESS
Question 1
Why do astronomers build radio telescopes?
Question options:
a) Radio waves give a different view of the universe b) Radio waves from space reach
the Earth's surface c) Radio telescopes can detect signals from aliens d) Radio
telescopes can be much larger than optical telescopes
Correct Answer: A
Rationale: Astronomers build radio telescopes primarily because radio waves provide
a unique and different view of the universe compared to visible light. Many celestial
objects and phenomena emit strongly in radio wavelengths but are invisible in optical
light. Radio waves can penetrate interstellar dust and gas clouds that block visible
light, allowing us to observe regions and processes that would otherwise be hidden.
While options b and d are true (radio waves do reach Earth's surface and radio
telescopes can be very large), the main scientific reason is the different information
radio waves carry about the universe.
Question 2
What type of telescope is most likely to suffer from chromatic aberration and have a
low light-gathering power?
Question options:
a) a small diameter reflecting telescope b) a large diameter reflecting telescope c) a
small diameter refracting telescope d) a large diameter refracting telescope
Correct Answer: C
Rationale: * Chromatic Aberration: This optical defect occurs when different colors of
light are focused at slightly different points, resulting in colored fringes around images.
It is inherent to refracting telescopes (which use lenses) because lenses bend
different wavelengths of light by different amounts. Reflecting telescopes (which use
, mirrors) do not suffer from chromatic aberration. * Light-gathering power: This is
directly proportional to the square of the diameter of the objective lens or mirror. A
small diameter telescope will have a low light-gathering power.
Combining these two points, a small diameter refracting telescope will suffer from
chromatic aberration and have low light-gathering power.
Question 3
When does chromatic aberration occur in a telescope?
Question options:
a) when different colours of light do not focus at the same point in a reflecting
telescope b) when different colours of light do not focus at the same point in a
refracting telescope c) when light of different wavelengths gets absorbed by the mirror
in a reflecting telescope d) when light of different wavelengths gets absorbed by the
lens in a refracting telescope
Correct Answer: B
Rationale: Chromatic aberration is an optical distortion that occurs in refracting
telescopes (those that use lenses). It happens because different wavelengths (colors)
of light are refracted (bent) at slightly different angles when passing through a lens,
causing them to focus at different points. This results in a blurry image with colored
fringes. Reflecting telescopes, which use mirrors to focus light, do not suffer from
chromatic aberration.
Question 4
What type of telescope is a radio telescope?
Question options:
a) reflecting b) refracting c) deflecting d) retracting
Correct Answer: A
Rationale: Radio telescopes are a type of reflecting telescope. They use a large, dish-
shaped antenna (the primary mirror) to collect and focus radio waves from space onto
ANSWERS) | ASSURED SUCCESS
Question 1
Why do astronomers build radio telescopes?
Question options:
a) Radio waves give a different view of the universe b) Radio waves from space reach
the Earth's surface c) Radio telescopes can detect signals from aliens d) Radio
telescopes can be much larger than optical telescopes
Correct Answer: A
Rationale: Astronomers build radio telescopes primarily because radio waves provide
a unique and different view of the universe compared to visible light. Many celestial
objects and phenomena emit strongly in radio wavelengths but are invisible in optical
light. Radio waves can penetrate interstellar dust and gas clouds that block visible
light, allowing us to observe regions and processes that would otherwise be hidden.
While options b and d are true (radio waves do reach Earth's surface and radio
telescopes can be very large), the main scientific reason is the different information
radio waves carry about the universe.
Question 2
What type of telescope is most likely to suffer from chromatic aberration and have a
low light-gathering power?
Question options:
a) a small diameter reflecting telescope b) a large diameter reflecting telescope c) a
small diameter refracting telescope d) a large diameter refracting telescope
Correct Answer: C
Rationale: * Chromatic Aberration: This optical defect occurs when different colors of
light are focused at slightly different points, resulting in colored fringes around images.
It is inherent to refracting telescopes (which use lenses) because lenses bend
different wavelengths of light by different amounts. Reflecting telescopes (which use
, mirrors) do not suffer from chromatic aberration. * Light-gathering power: This is
directly proportional to the square of the diameter of the objective lens or mirror. A
small diameter telescope will have a low light-gathering power.
Combining these two points, a small diameter refracting telescope will suffer from
chromatic aberration and have low light-gathering power.
Question 3
When does chromatic aberration occur in a telescope?
Question options:
a) when different colours of light do not focus at the same point in a reflecting
telescope b) when different colours of light do not focus at the same point in a
refracting telescope c) when light of different wavelengths gets absorbed by the mirror
in a reflecting telescope d) when light of different wavelengths gets absorbed by the
lens in a refracting telescope
Correct Answer: B
Rationale: Chromatic aberration is an optical distortion that occurs in refracting
telescopes (those that use lenses). It happens because different wavelengths (colors)
of light are refracted (bent) at slightly different angles when passing through a lens,
causing them to focus at different points. This results in a blurry image with colored
fringes. Reflecting telescopes, which use mirrors to focus light, do not suffer from
chromatic aberration.
Question 4
What type of telescope is a radio telescope?
Question options:
a) reflecting b) refracting c) deflecting d) retracting
Correct Answer: A
Rationale: Radio telescopes are a type of reflecting telescope. They use a large, dish-
shaped antenna (the primary mirror) to collect and focus radio waves from space onto
