Which main sequence stars have the shortest lifetimes?
A) spectral type M
B) spectral type G
C) spectral type O
D) spectral type A
E) can't tell from information provided
C) spectral type O
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An electron moves in a region where the magnetic field is uniform and has a magnitude of 80 ?T. The electron follows a helical path which has a pitch of 9.0 mm and a radius of 2.0 mm. What is the speed of this electron as it moves in this region?
A. 48 km/s B. 28 km/s C. 20 km/s D. 35 km/s E. 8.0 km/s
The figures below represent interference fringes. The distances from the screen to the slits is the same for each figure, and the planes of the screen and the slits are parallel. In each figure the spacing d between the slits is the same. Which figure(s) represent(s) slits illuminated with light of the shortest wavelength ?? The white spaces represent the interference maxima
a.
I.
b.
II.
c.
III.
d.
IV.
e.
V.
In the original Miller—Urey experiment it was assumed that carbon and nitrogen in the early atmosphere were present as
A) carbon dioxide (CO2 ) and nitrogen (N2) B) carbonates (CO3-) and nitrates (NO3-) C) methane (CH4 ) and ammonia (NH3) D) carbon and nitrogen atoms
The observed composition of ordinary matter in the universe—roughly 75 percent hydrogen and 25 percent helium by mass—closely matches theoretical predictions based on the Big Bang model
Indicate whether the statement is true or false