astro t3w2

Multiple Choice

The equation describing the shape of the radiance against wavelength graph of a blackbody is

• Planck's law

• Stefan Boltzmann law

• Wien's law

• Tully-Fischer relation

• No Hair Theorem

Multiple Choice

Blackbody radiation is due to/dependent on

• emission

• absorption

• temperature

• the dark

Multiple Choice

The temperature of the Cosmic Microwave Background is 2.725K. Calculate its peak wavelength given that b=0.0029m/K.

• 1cm

• 1mm

• 1m

• 1km

Multiple Choice

Star A has a luminosity twice that of star B. The magnitude of Star B is:

• half of star A

• magnitude of A + 2

• magnitude of A + lg(2)

• magnitude of A + 2.5lg(2)

Multiple Choice

Star A has an apparent magnitude m, and star B has an apparent magnitude m+1. What is the distance from the observer to star B given that the distance of star A from the observer is d?

• d*(10^5)

• d*(10^(1/5))

• 2d

• d/2

Multiple Select

On the Hayashi Track, a pre-main sequence star moves downwards on the HR diagram. This means that:

• The star's temperature decreases

• The star's luminosity increases

• The star's luminosity decreases

• The star's radius becomes larger

• The star's radius becomes smaller

Multiple Choice

J. Ray is observing the light emitted by a nearby star. He observed that the star has a peak wavelength of 290 nm. Calculate the star’s surface temperature.

• 9000K

• 99999K

• 99K

• 9990K

Multiple Choice

Population II stars are _____________ compared to population I stars

• more metallic, older

• less metallic, older

• more metallic, younger

• less metallic, older

Multiple Choice

Our Sun is a G2V star. The V indicates that

• The sun is on the main sequence

• The sun is hotter than a G2IV star and cooler than a G2VI star

• The sun is a subgiant

• The sun is yellow

Multiple Select

The horizontal axis of the HR diagram indicates (left to right)

• colour, in increasing B-V

• Temperature, in decreasing temp

• temperature class, from O to M

Multiple Choice

The MK classification system for spectral type, in order of increasing temperature, is

• OBAFGKM

• MKGFABO

• ABCDEFG

• OFGMKBA

Multiple Choice

the colour-magnitude HR diagram has what as the vertical axis?

• Mv, magnitude in visual band

• Mbol, bolometric magnitude

• luminosity

• temperature