The mass enclosed in any orbit can be estimated from the equation M(

A) The mass is spread out over large radius.
B) The mass is concentrated in the center.
C) The mass is distributed like a doughnut, with a hole in the center.
D) Cannot be determined from the information given.

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B

Physics & Space Science

In a solar cell the light initially passes through the n-type silicon to reach the pn-junction where it is desired that the light absorption occur. If we want at least 90 percent of the light entering a silicon solar cell to reach the pn-junction region, what is the maximum thickness of the n-type material for 0.6 ?m light assuming pure silicon?

What will be an ideal response?

Applications to Astronomy: Estimate the speed of recession of a galaxy that is 10 billion light-years away if H = 20 ? (c = 3.00 × 108 m/s)

A. 0.1c B. 0.3c C. 0.5c D. 0.7c

Estimate the observed wavelength for the 656 nm line in the spectrum of a star which is 100 million light-years from us

A) 653 nm B) 659 nm C) 661 nm D) 677 nm E) 692 nm

44 g of petrified wood was found in a petrified forest. A sample showed a 14C activity of 100 decays/minute. How long has the tree been dead (in years)? (The half-life of carbon-14 is 5730 years and freshly cut wood contains 6.5 × 10^10 atoms of 14C per gram.)

a. 12 300 b. 15 600 c. 8 500 d. 4 700 e. 2 400