Ultimate Astronomy

Question 1

A filament's initial temperature is 4000K. The filament temperature is then adjusted to 5000K by turning a knob. There is more red light emanating from the filament.

Accepted Answer

Finally, when it is at 5000K

Answer

The same for these two cases

Answer

Not enough information to solve

Answer

Initially, when it is at 4000K.

Question 2

Imagine a star with the same temperature on its surface but twice the sun's surface area. What is the energy flux at that star's surface if the energy flux at the sun's surface is Fsun?

Accepted Answer

Fsun

Answer

Fsun/2

Answer

2 Fsun

Answer

16 Fsun

Question 3

Imagine a star that is twice as big as the sun and has the same surface temperature. What is the total energy emitted by a star per second if the sun emits P watts of energy every second?

Accepted Answer

2 P Watts

Answer

4 P Watts

Answer

P/2 Watts

Answer

P Watts

Question 4

How much more total radiated power per square meter (energy Flux) would we receive on Earth if the sun's temperature doubled?

Accepted Answer

Sixteen times (2^4)

Answer

Eight times (2^3)

Answer

Twice

Answer

Four times (2^2)

Question 5

The surface of the sun is a good representation of a black body. Let's say the temperature of the sun doubled overnight. In that case, which of the following claims would be accurate?

Accepted Answer

The sun would look bluer and radiate more power

Answer

The sun would look bluer but radiate less power

Answer

The sun would look redder and radiate less power

Answer

The sun would look redder and radiate more power

Question 6

Like our own, the hot, dense cores of stars are surrounded by low-density gaseous atmospheres. What kind of spectrum might you see if observing the light spectrum from the sun or any other star?

Accepted Answer

Absorption line

Answer

Emission line

Answer

Continuous

Question 7

The moon's diameter (or radius) is approximately one-fourth that of the earth. What percentage of Earth's mass would the moon's mass be if its density and that of the planet were equal?

Accepted Answer

1/64

Answer

1/16

Answer

1/4

Answer

1/8