Constellations — Homi Bhabha Class 9 Physics MCQs with Solutions
Free Homi Bhabha Class 9 Physics Constellations 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 — Constellations · medium · theory
A constellation is:
A. a group of galaxies
B. a single very bright star
C. a cluster of planets
D. a group of stars that appears to form a recognisable pattern in the sky ✓ Correct
Solution: A constellation is a recognisable pattern formed by stars as seen from Earth.
Q2 — Constellations · medium · theory
The constellation Ursa Major is also known in India as:
A. Orion
B. Sirius
C. Saptarshi ✓ Correct
D. Mrig
Solution: Ursa Major (the Great Bear / Big Dipper) is called Saptarshi in India.
Q3 — Constellations · hard · theory
The Pole Star (Dhruva Tara) appears almost stationary in the sky because it lies:
A. nearly above the axis of rotation of the Earth ✓ Correct
B. on the equator
C. at the centre of the solar system
D. very close to the Earth
Solution: The Pole Star is nearly in line with the Earth's rotational axis, so it barely appears to move.
Q4 — Constellations · hard · theory
The two "pointer stars" of Ursa Major are useful because they:
A. point towards the Pole Star ✓ Correct
B. point towards the Sun
C. point towards the Moon
D. always point east
Solution: A line through the two end stars of the Big Dipper points to the Pole Star, aiding navigation.
Q5 — Constellations · medium · theory
Constellations appear to move slowly across the night sky mainly because of:
A. the expansion of space
B. the Moon's gravity
C. the Earth's rotation ✓ Correct
D. the stars orbiting the Earth
Solution: The apparent motion of constellations is due to the Earth spinning on its axis.
Q6 — Constellations · hard · theory
The stars that make up a constellation are:
A. all at the same distance from Earth
B. all part of the solar system
C. physically bound close together
D. usually at very different distances and not physically close to one another ✓ Correct
Solution: Stars in a constellation merely appear together from Earth; they are actually at widely different distances.
Q7 — Constellations · easy · theory
A constellation is best described as:
A. A recognizable pattern of stars as seen from Earth, whose stars may actually lie at very different distances ✓ Correct
B. A group of stars that are physically close together and held by gravity
C. A single very bright star
D. A cloud of glowing gas and dust in space
Solution: Stars in a constellation only appear grouped because they lie along nearly the same direction from Earth. In reality they can be at hugely different distances and are usually not related to one another.
Q8 — Constellations · easy · theory
The constellation Ursa Major (the Big Dipper, or Saptarishi) is often used by observers to locate which important star?
A. The Sun
B. Sirius, the brightest night star
C. Polaris, the Pole Star ✓ Correct
D. Betelgeuse, a red giant
Solution: The two stars at the outer edge of the Big Dipper bowl are the pointer stars. A line drawn through them points almost directly to Polaris, the Pole Star, which sits above the northern horizon.
Q9 — Constellations · medium · theory
The constellation Orion is easily seen in the winter night sky but is not visible during summer nights. The main reason is that:
A. Orion physically moves far away from Earth in summer
B. Earth revolves around the Sun, so in summer the Sun lies in the direction of Orion and it is above the horizon in the daytime ✓ Correct
C. The stars of Orion stop shining during summer
D. Orion is always hidden behind the Moon in summer
Solution: As Earth orbits the Sun, our night side faces different directions of space through the year. In summer, Orion lies roughly behind the Sun, so it is up during the day and lost in the Sun glare instead of in the night sky.
Q10 — Constellations · hard · theory
Every star, including those forming a constellation, drifts slowly across space (proper motion). What does this imply about constellation shapes over very long times?
A. They slowly change shape over tens of thousands of years as the stars shift relative to one another ✓ Correct
B. They stay exactly fixed forever
C. They change shape noticeably from one year to the next
D. They flip left-to-right every single night
Solution: Proper motions are tiny over a human lifetime, so patterns look fixed to us. But over tens of thousands of years the different individual motions accumulate and the familiar shapes gradually distort.