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zheka24 [161]
3 years ago
8

What is a star's main fuel during its lifetime? A. hydrogen B. carbon C. helium D. oxygen

Physics
1 answer:
Flura [38]3 years ago
6 0
<span>The star's main fuel during its lifetime is hydrogen. It is said that a star is composed of 97% hydrogen and 3% helium. Once the hydrogen of a star is gone, the star becomes old because it burns hydrogen during its lifetime.</span>
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Calculate the index of refraction for a medium in which the speed of light is 2.1x 108 m/s. The speed of light in vacuum is 3x10
strojnjashka [21]

Answer:

n = 1.42

Explanation:

The refractive index for a medium is given by the ratio of the speed of light in vacuum to the speed of light in a medium.

n=\dfrac{c}{v}\\\\n=\dfrac{3\times 10^8}{2.1\times 10^8}\\\\n = 1.42

So, the refractive index of the medium is 1.42.

5 0
3 years ago
What is latitude 20 degrees north and longitude 65 degrees west?
Marta_Voda [28]
<span>The latitude 20 degrees north and longitude 65 degrees west is in the Atlantic Ocean, north of Puerto. The north coast region of Puerto Rico named "Porta Atlantico" faces the dark blue Atlantic Ocean. On the off chance that you long for unwinding on a tranquil shoreline, losing all sense of direction in the magnificence of waves smashing, and being calmed by their song, you might need to remain on the north drift, lease an auto and investigate.</span>
3 0
3 years ago
What is a non-example of Newton's 3rd law of motion?
kirill [66]

Answer:

Unbalanced forces are not examples of Newton's third law because not all opposite reactions are unbalanced forces.

Explanation:

4 0
3 years ago
In preparation for the final exam, our astronomy study group has reconvened to discuss Mercury's unique orbital properties. They
grigory [225]

Answer:

The only incorrect statement is from student B

Explanation:

The planet mercury has a period of revolution of 58.7 Earth days and a rotation period around the sun of 87 days 23 ha, approximately 88 Earth days.

Let's examine student claims using these rotation periods

Student A. The time for 4 turns around the sun is

           t = 4 88

           t = 352 / 58.7 Earth days

In this time I make as many rotations on itself each one with a time to = 58.7 Earth days

           #_rotaciones = t / to

           #_rotations = 352 / 58.7

           #_rotations = 6

therefore this statement is TRUE

student B. the planet rotates 6 times around the Sun

          t = 6 88

          t = 528 s

The number of rotations on itself is

           #_rotaciones = t / to

           #_rotations = 528 / 58.7

           #_rotations = 9

False, turn 9 times

Student C. 8 turns around the sun

           t = 8 88

           t = 704 days

the number of turns on itself is

            #_rotaciones = t / to

            #_rotations = 704 / 58.7

            #_rotations = 12

True

The only incorrect statement is from student B

6 0
3 years ago
All of the following processes are the ones that lead directly to the formation of sedimentary rock EXCEPT-
emmasim [6.3K]

Answer:

melting of rock deep underground.

Explanation:

The melting of rocks deep underground does not produce sedimentary rocks. Most igneous rocks are produced by this process.

When molten rocks underground called magma is solidified in the subsurface, it results into the formation of igneous bodies.

  • Sedimentary rocks forms by the accumulation of sediments.
  • Inside the basin where the sediments are deposited, they are compacted, cemented and lithified.
  • Chemical and physical weathering of rocks produces sediments.
4 0
3 years ago
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