Astronomy

Question 1

Astronomy

Answer 1

• the science of objects outside earths atmosphere
• stars emit EMR, we study them using telescopes

Question 2

EMR emitted by the sun

Answer 2

-the surface of the sun emits visible light and IR
- emits all EMR but only a fraction reaches the earths surface

Question 3

Earths atmosphere

Answer 3

-Atmosphere filters all EMR except radio waves and EMR close to the visible spectrum from reaching earth.

Question 4

Gases that absorb radiation

Answer 4

-Oxygen/ozone- UV radiation
- H2O/CH4/CO2- IR
- X-rays (solar flares) and gamma rays created in the cone and are absorbed by solar plasma as they make their way to the surface of the sun and are remitted at lower frequencies

• these collisions ioznine the atoms and liberate electrons which absorb long wavelength radio waves

Question 5

Properties of light

Answer 5

1. Reflection- wave bounces off surface
2. Refraction- bending of light
3. Polarization- forcing a wave to vibrate in only one direction
4. Diffraction- bending of a wave as it passes through and object/opening

Question 6

Reflection

Answer 6

• the wave bounces off a barrier, the angle of incidence is equal to the angle of reflection

Question 7

Refraction

Answer 7

• when a wave strikes a boundary to a new medium ( in which it travels at a different speed), it will bend or refract
• index of refraction for air is 1.00 and water is 1.33

Moving from a low to high index bends towards the normal

Question 8

Polarization

Answer 8

• when light is made to vibrate in same direction only
• you can actually stop light from going through a surface by using 2 polarizing filters
• polarizing sunglasses protect the eyes from glare from the sun as they absorb the light reflected from the horizontal surface.

Question 9

Diffraction grating

Answer 9

• piece of glass or plastic with thousands of tiny spaced lines etched on its surface to produce spectra.
• bending of a wave as it passes the edges of an opening
• different colours of lights will refract by different amounts when they pass through a prism.

Question 10

Total internal reflection

Answer 10

• A propagating wave strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface
• the result is the wave is reflected from the surface