Astrophysics Practice Questions
A-Levels · A-Level Physics · 149 free MCQs with instant results and detailed explanations.
149
Total
56
Easy
73
Medium
20
Hard
Start Practicing Astrophysics
Take a timed quiz or customize your practice session
Sample Questions from Astrophysics
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the main source of energy for stars like the Sun?
A.
Nuclear fusion
B.
Chemical reactions
C.
Gravitational contraction
D.
Radiation from outer space
Show Answer & Explanation
Correct Answer: A
The Sun produces energy primarily through nuclear fusion, where hydrogen atoms combine to form helium, releasing vast amounts of energy in the process.
Q2
Easy
Which of the following describes the term 'light year'?
A.
The time it takes for light to travel from the Earth to the Sun
B.
A unit of distance that light travels in one year
C.
The distance covered by light in one second
D.
The speed at which light travels in a vacuum
Show Answer & Explanation
Correct Answer: B
A light year is a unit of distance used in astronomy, defined as the distance that light travels in one year, approximately 9.46 trillion kilometers.
Q3
Easy
What phenomenon causes the apparent shift in position of a star when observed from different locations on Earth?
A.
Parallax
B.
Refraction
C.
Aberration
D.
Doppler effect
Show Answer & Explanation
Correct Answer: A
Parallax is the apparent shift in position of a star due to the change in the observer's location, allowing astronomers to measure distances to nearby stars.
Q4
Medium
What is the primary reason for the formation of planets in a protoplanetary disk?
A.
Gravitational attraction of dust and gas
B.
Cosmic radiation
C.
Electromagnetic forces
D.
Nuclear fusion
Show Answer & Explanation
Correct Answer: A
Planets form primarily due to the gravitational attraction of dust and gas in a protoplanetary disk, leading to the accumulation and coalescence of material.
Q5
Medium
If a star is moving away from an observer, which phenomenon explains the observed increase in its wavelength?
A.
Doppler Effect
B.
Redshift
C.
Spectral Scattering
D.
Photoelectric Effect
Show Answer & Explanation
Correct Answer: B
The observed increase in wavelength for a star moving away from an observer is referred to as redshift, which is a consequence of the Doppler Effect.
Q6
Medium
Which of the following types of radiation is primarily emitted by black holes due to quantum effects near the event horizon?
A.
Gamma rays
B.
X-rays
C.
Hawking radiation
D.
Visible light
Show Answer & Explanation
Correct Answer: C
Black holes emit Hawking radiation due to quantum effects at the event horizon, which is a theoretical prediction by Stephen Hawking.
Q7
Medium
What is the relationship between a star's temperature and its spectral classification?
A.
Higher temperatures correspond to later spectral types.
B.
Higher temperatures correspond to earlier spectral types.
C.
Temperature does not affect spectral classification.
D.
Spectral classification is unrelated to temperature.
Show Answer & Explanation
Correct Answer: B
Higher temperatures in stars correspond to earlier spectral types (O, B, A) while cooler stars correspond to later types (K, M). This classification is based on temperature and resulting spectral characteristics.
Q8
Hard
In a binary star system, one star is observed to have a mass twice that of the other star. If the center of mass is located closer to the more massive star, what ratio of distances from the center of mass to each star can be determined?
A.
1:2
B.
2:1
C.
1:1
D.
3:1
Show Answer & Explanation
Correct Answer: B
The center of mass (COM) is closer to the more massive object, so the distance from the COM to the lighter star must be greater. Thus, if mass M_1 is twice M_2, the ratio of distances from the COM to each star is inversely proportional to their masses, leading to a 2:1 ratio.
Q9
Hard
A galaxy is moving away from Earth with a velocity of 0.8c, where c is the speed of light. According to the Doppler effect, what is the observed wavelength of light emitted from a star in this galaxy, which originally emits light at a wavelength of 500 nm?
A.
1000 nm
B.
600 nm
C.
500 nm
D.
400 nm
Show Answer & Explanation
Correct Answer: A
For a receding source, the observed wavelength increases due to the Doppler effect. The formula for the observed wavelength (ฮป') is ฮป' = ฮป(1 + z), where z is the redshift. For a velocity of 0.8c, z โ 0.6, leading to ฮป' โ 500 nm ร (1 + 0.6) = 1000 nm.
Q10
Hard
A star is observed to have a parallax angle of 0.1 arcseconds. Calculate its distance from Earth in parsecs.
A.
10 parsecs
B.
20 parsecs
C.
5 parsecs
D.
30 parsecs
Show Answer & Explanation
Correct Answer: A
The distance to a star in parsecs is given by the formula: distance (pc) = 1 / parallax angle (arcseconds). Here, the parallax angle is 0.1 arcseconds, so the distance is 1 / 0.1 = 10 parsecs.
Showing 10 of 149 questions. Start a quiz to practice all questions with scoring and timer.
Practice All 149 Questions →Astrophysics โ A-Levels A-Level Physics Practice Questions Online
This page contains 149 practice MCQs for the chapter Astrophysics in A-Levels A-Level Physics. The questions are organized by difficulty โ 56 easy, 73 medium, 20 hard โ so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.