Telescopes — Homi Bhabha Class 9 Physics MCQs with Solutions
Free Homi Bhabha Class 9 Physics Telescopes MCQs with step-by-step solutions (10 questions). Part of Observing Space / Astronomy. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Telescopes · medium · theory
A telescope is used to:
A. record sound from space
B. observe distant celestial objects by collecting more light ✓ Correct
C. magnify very small nearby objects
D. measure temperature of stars directly
Solution: A telescope gathers light from far-off objects, making them appear brighter and larger.
Q2 — Telescopes · hard · theory
A refracting telescope forms images using ______, while a reflecting telescope uses ______:
A. prisms; lenses
B. mirrors; lenses
C. mirrors; prisms
D. lenses; mirrors ✓ Correct
Solution: Refractors use lenses to bend light; reflectors use curved mirrors to gather and focus it.
Q3 — Telescopes · medium · theory
The famous space telescope that orbits the Earth above the atmosphere is the:
A. Galileo telescope
B. Radio telescope at Pune
C. Hubble Space Telescope ✓ Correct
D. INSAT
Solution: The Hubble Space Telescope orbits Earth, giving clear images free of atmospheric distortion.
Q4 — Telescopes · hard · theory
A telescope with a larger objective (aperture) is better because it:
A. magnifies without any lens
B. collects more light and can show fainter objects ✓ Correct
C. is cheaper to build
D. needs no focusing
Solution: A bigger aperture gathers more light, allowing fainter and more distant objects to be seen.
Q5 — Telescopes · medium · theory
A radio telescope is used to detect ______ coming from space:
A. visible light only
B. X-rays only
C. sound waves
D. radio waves ✓ Correct
Solution: Radio telescopes collect radio-wave signals emitted by celestial objects.
Q6 — Telescopes · medium · theory
The scientist who first used a telescope to study the sky (observing Jupiter's moons and craters on the Moon) was:
A. Isaac Newton
B. Galileo Galilei ✓ Correct
C. C. V. Raman
D. Albert Einstein
Solution: Galileo pioneered telescopic astronomy in the early 17th century.
Q7 — Telescopes · easy · theory
A refracting telescope forms images of distant objects mainly using:
A. Prisms only
B. Radio antennas
C. Curved mirrors
D. Lenses ✓ Correct
Solution: A refracting telescope uses lenses to bend (refract) and focus light. A reflecting telescope, by contrast, uses curved mirrors to gather and focus the light.
Q8 — Telescopes · medium · theory
The chief advantage of a telescope with a larger objective (a wider aperture) is that it:
A. Makes every image far more colourful
B. Gathers more light, so fainter and more distant objects become visible ✓ Correct
C. Weighs much less than a small telescope
D. Uses much less electricity
Solution: A wider objective collects more light. Because faint objects send us very little light, a larger aperture lets us detect stars and galaxies that a smaller telescope cannot show.
Q9 — Telescopes · medium · numerical
A telescope has an objective lens of focal length 100 cm and an eyepiece of focal length 5 cm. Its angular magnification is:
A. 500 times
B. 20 times ✓ Correct
C. 5 times
D. 95 times
Solution: For a telescope, magnification = focal length of objective divided by focal length of eyepiece = 100 divided by 5 = 20 times.
Q10 — Telescopes · hard · numerical
Telescope B has an objective whose diameter is 3 times that of telescope A. Since light-gathering power depends on the area of the objective, telescope B collects about how many times more light than A?
A. 27 times
B. 9 times ✓ Correct
C. 6 times
D. 3 times
Solution: Light-gathering power is proportional to the area of the objective, which varies as the diameter squared. Tripling the diameter gives 3 squared = 9 times the area, so B gathers about 9 times more light.