Astronomers know the universe is expanding because:
A) everything is moving away from us.
B) all stars are moving away from us.
C) most galaxies are moving away from us.
D) galaxies farther away are moving away from us faster.
E) there is a cosmic microwave background.
D
You might also like to view...
The disk component of our Galaxy has an overall relatively red color
Indicate whether the statement is true or false
The proton contains which of the following combination of quarks?
a. two up quarks and one down quark b. one up quark and two down quarks c. one top quark and two bottom quarks d. two top quarks and one bottom quark
A 95 N force exerted at the end of a 0.50 m long torque wrench gives rise to a torque of 15 N • m. What is the angle (assumed to be less than 90°) between the wrench handle and the direction of the applied force?
A) 18° B) 14° C) 22° D) 25°
A solar cell has a light-gathering area of 10 cm2 and produces 0.2 A at 0.8 V (DC) when illuminated with S = 1 000 W/m2 sunlight. What is the efficiency of the solar cell?
a. 16% b. 7% c. 23% d. 4% e. 32%