Question

9/ The star Betelgeuse has a wavelength of maximum emission of 923.5 nm, whereas the star Bellatrix has a wavelength of maximum emission of 131.8 nm. Which star is colder

A/ more info

B/ Bellatrix

C/ Betelgeuse

D/ same temperature

10/ Which of the following correctly lists the spectral sequence of stars in order of decreasing surface temperature?

A/ O,B,A,F,G,K,M

B/ M,K,G,F,A,B,O

C/ O,M,K,G,F,B,A

D/ A,B,F,G,K,M,O

11/ How is a star assigned its spectral type?

A/ The star’s spectrum is taken, and its spectral type is assigned based on the amount of green light present in its spectrum

B/ The star’s thermal energy is measured and from that its surface temperature is calculated, the value of the star’s surface temperature determines its spectral type

C/ Images of a star are taken, and its spectral type is assigned based on the star’s brightness

D/ The star’s spectrum is taken, and its spectral type is assigned based on the spectral lines observed

12/ Which of these stars has the coolest surface temperature?

A/ an A star

B/ an F star

C/ a G star

D/ a K star

13/ Which of these stars would be the most luminious?

A/ A white dwarf

B/ An A-type main sequence star

C/ A K-type main sequence star

D/ A B-type main sequence star

14/ which of these stars is the most massive ?

A/ a main sequence type T star

B/ a main sequence type G star

C/ a main sequence type M star

D/ a main sequence type A star

Answer 1

9:- The lesser the wavelength of maximum emission, the greater the temperature, therefore Betelgeuse is cooler.

10 :- The system of spectral sequence puts the stars into seven broad groups in order of decreasing temperature: O, B, A, F, G, K, and M.  Option A

11:- Electromagnetic radiation received from the star is analysed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colours interspersed with spectral lines.

Option D

12:- According to stellar classification out of the given stars a K star has the coolest surface temperature.

13:- Out the given choice a B-Type main sequence star is the most luminous.