CIV300 Test 1 Solutions to Post -Fall 2013(2)

4 marks step 1 total energy output from star above

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: by our atmosphere’s gases e.g. CO2, water vapour Two of which could be: • light reflected directly back from ice/snow/high albedo surface • Heat reflected back to space from the tops of clouds • Heat radiated back to space from clouds • Heat radiated back to space from greenhouse gases 2. A distant star of radius 100 million km has a surface temperature of 3,000K. Calculate its energy generated per m2 of surface area. Using the Stefan Boltzmann equation, E = σT4 = 5.67 x 10-8 x (3000)4 = 4.59 x 106W or equivalent in kW. If a planet of radius 5,000km without an atmosphere is orbiting at a distance of 1 billion km from the star, what is the average energy intensity that will fall onto the planet per m2 of its surface area? (4 marks) Step 1 Total energy output from star = Above answer x star’s surface area = 4.59 x 106W x 4x pi x (100x109)2 = 5.77x1029 W/m2 Step 2 At our orbit, this amount is spread thinly over a sphere equal to the orbit. Energy intensity at that orbit is: = 5.77x1029 W/m2 / 4x pi x r2 where r is the planet’s orbit = 5.77x...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online