Universe

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What is the name given to a star with a radius of about 10 km?

Black Hole
Neutron Star (correct)
Supernova
White Dwarf

Which of the following statements is true about a star's magnitude?

A star with a negative magnitude is brighter than a star with a zero magnitude. (correct)
A star's magnitude is a measure of its distance from Earth.
A star with a magnitude of zero is the brightest star in the sky.
A star with a negative magnitude is less bright than a star with a zero magnitude.

What is the maximum mass of a star that can become a white dwarf?

2 M (correct)
1 M
10 M
5 M

What is the term for the total energy radiated into space per second from the surface of a star?

Absolute luminosity (A) Signup and view all the answers

What is the average distance from the Earth to the Sun?

1.49 × 10^8 km (A) Signup and view all the answers

What is the condition for the formation of a black hole?

If the star's mass is greater than 5M. (D) Signup and view all the answers

What happens to the photons emitted by a black hole?

They cannot escape from its surface due to strong gravitational pull. (D) Signup and view all the answers

What is the result of the combination of electrons and protons in a neutron star?

The formation of neutrons. (A) Signup and view all the answers

What is the relation between the brightness of a star and its magnitude?

The brightness of a star is inversely proportional to its magnitude. (D) Signup and view all the answers

What is the magnitude of a star with a brightness of l?

0 (D) Signup and view all the answers

What is the surface temperature of a star classified as 'F' type according to its spectral type?

7.5  10^3 K (B) Signup and view all the answers

What is the relationship between the colour of a star and its temperature, as expressed by Wien's displacement law?

λm ∝ 1/T (B) Signup and view all the answers

What can be used to find the masses of two stars in a binary system?

Equation (iii) (A) Signup and view all the answers

What is the spectral type of our sun?

G (A) Signup and view all the answers

What is the total energy radiated by a star per second, given by?

E = σT^4 × 4πR^2 (B) Signup and view all the answers

What is the primary factor that determines the spectral type of a star?

Surface temperature (C) Signup and view all the answers

Which of the following statements is true about the energy radiated by a star?

It is directly proportional to its surface temperature (D) Signup and view all the answers

What is the colour of a star with a surface temperature of approximately 1.5 × 10⁴ K?

Blue (B) Signup and view all the answers

What is the significance of the parameter σ in the equation for the energy radiated by a star?

It is the Stefan-Boltzmann constant (A) Signup and view all the answers

What is the relationship between the spectral type of a star and its colour?

The surface temperature determines both the spectral type and the colour (B) Signup and view all the answers

What is the estimated number of pulsars in the universe?

100 (B) Signup and view all the answers

What is the minimum wavelength of light associated with the hottest stars in the galaxy?

Blue (A) Signup and view all the answers

What is the approximate mass of the Milky Way galaxy?

150 solar masses (C) Signup and view all the answers

What is the characteristic of the electromagnetic waves emitted by a pulsar?

Pulsating (B) Signup and view all the answers

What is the term for a group of stars that are gravitationally bound together?

Star Cluster (C) Signup and view all the answers

What is the primary reason for the formation of a comet's tail?

Heat from the Sun's radiation (C) Signup and view all the answers

What is the name of the method used to measure the distance of nearby stars?

Parallax method (D) Signup and view all the answers

What is a characteristic feature of stars?

They are countless in number (A) Signup and view all the answers

What is the reason for the twinkling of stars at night?

Atmospheric refraction (D) Signup and view all the answers

What is a characteristic of a star's motion?

It appears to move from west to east (B) Signup and view all the answers