We need to use Wien's Law
Wavelength = 0.0028976 [m.K] / T
This establishes a relation between the wavelength and temperature of a black body (any body that absorbs radiation, such as the stars)
T = 0.0028976 [m.K]/290 E-9[m] = 9991.724 K
If the boat is i travling at 10 m/s and the river is 8.0 m/s the boats speed is 18.0 m/s
The phrase "light year" is a <u><em>distance</em></u> ... it's the distance that light travels through vacuum in one year.
When you look at an object located 1 light year away from you, you see it as it was 1 year ago.
If a star located 10 light years away from us suddenly brightens, or dims, or explodes, we see the event <em>10 years later.</em>
"1 watt" means 1 joule of energy per second.
75 W means 75 joules/sec .
Energy = (75 Joule/sec) x (12 min) x (60 sec/min)
Energy = (75 x 12 x 60) (Joule-<em>min-sec</em> / <em>sec-min</em>)
<em>Energy = 54,000 Joules</em>
