Compare an amateur telescope of 100 mm (a typical"4-inch" telescope, usually a refractor) with that of the Keck telescope,which is 10 meters across. [Hint: Work in powers of ten; "2 decimals" means after the decimal point in powers of ten notation.]

(b) Area of 100-mm objective in m : _______________ m (Careful! Note the conversion from millimeters to meters . Working with powers of ten can make this step easier. Hint: How many mm in 1 meter? How many mm2in 1 m2?)[Round to2decimals]

Score:__________________________

(a) Area of 100-mm objective in mm2: _______________ mm2[Use scientific notation and round to2decimals; same for partb]2222

(c) Area of 10-m Keck objective: ____________________ m2[Use in scientific notation and round to2decimals]

(d) 10-m objective collects _______________ times the light of a 100-mm objective[Round tonearestwhole number]

(e) The answer to (d) represents how many magnitudes? _______________

(Hint: Look for thexyfunction on a scientific calculator. If (2.512)5= 100 and represents 5 magnitude steps, then how2

many steps does the answer todrepresent? If 100 = 1010 or 10 , then how many powers of ten is the answer tod?)