Radiation

Question 1

Explain blueshifted

Answer 1

If an astronomical object is moving towards us, the light we receive from it is seen to be bluer than it truly is

Question 2

Explain redshifted

Answer 2

If an astronomical object is moving away from us, the light we receive from it is seen to be redder than it truly is

Question 3

Doppler effect and speed

Answer 3

V = c x ( delta wavelength / emitted wavelength )

Question 4

Explain radial velocity

Answer 4

The Doppler effect arises only when there is relative motion in the direction of the straight line joining the observer to the wave source

Question 5

black body

Answer 5

• Absorbs all radiation incident upon is. It will heat up and begin producing its own radiation. At some point, the amount of absorbed radiation is exactly balanced by the amount of emitted radiation.
• Stars behave very much like black bodies

Question 6

Explain radiation laws

Answer 6

• A black body emits radiation at all wavelengths, albeit with different intensity.
  - This is because there is always a spread in the energies of the particles making up an object
• A higher temperature produces higher power at all wavelengths
  - The higher the temperature, the shorter the wavelength at which maximum power is emitted

Question 7

Wien’s Law

Answer 7

calculated the wavelength, ƛmax

ƛmax = 3x10^6 / T