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Sergio [31]
3 years ago
6

Which statement correctly describes variable stars?

Physics
1 answer:
Kryger [21]3 years ago
5 0

Answer:

D)

Explanation:

The Period-Luminosity relationship tells us that luminosity increases with the period, and of course the more luminosity a star has the more far away they can be seen, so from this we know that:

A) False since lower luminosities can be observed when they are close.

B) False since longer periods means higher luminosities

C) False since lower luminosities can be observed when they are close.

D) True: Variable stars with shorter periods have lower luminosities, so they can only be observed when they are close.

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A circular dartboard has a radius of 2 meters and a red circle in the center. Assume you hit the target at a random point. For w
Sati [7]

Answer:

1.549 m

Explanation:

Given:

The radius of the circular board, r = 2 m

The probability of hitting the red is given as 0.6

Now, this probability of hitting the red can be conclude as

0.6 = (Area of red)/ (Total area of the board)

Total area of the board = πr² = π × 2²

let the radius of the red area be R

thus, area of red circle, = πR²

on substituting the value of the area, we have

0.6 = (πR²)/ (π × 2²)

or

R² = 2.4

or

R = 1.549 m

Thus, the radius of the red circle is 1.549 m

3 0
3 years ago
When monochromatic light passes through the interface between two unknown materials at an angle θ where 0∘<θ<90∘, no chang
kirill115 [55]

Answer:

the correct one is the first,   the refractive index of the two materials must be the same

Explanation:

When a beam of light passes through two materials, it must comply with the law of refraction

         n₁ sin θ₁ = n₂ sin θ₂

where n₁ and n₂ are the refractive indices of each medium.

In this case, it indicates that the light does not change direction, so the input and output angle of the interface must be the same,

       θ₁ = θ₂ = θ

substituting

          n₁ = n₂

therefore the refractive index of the two materials must be the same

When reviewing the answers, the correct one is the first

5 0
2 years ago
The three types of seismic waves are P waves, S waves and T waves. Please select the best answer from the choices provided T F
ikadub [295]
The correct answer is False
7 0
3 years ago
Read 2 more answers
Everything in the universe is made up of what A.atoms B.minerals C.nitrogen ​
Montano1993 [528]

Answer: A) Atoms.

Explanation:

5 0
3 years ago
Read 2 more answers
The small spherical planet called "Glob" has a mass of 7.88×1018 kg and a radius of 6.32×104 m. An astronaut on the surface of G
timama [110]

The orbiting speed of the satellite orbiting around the planet Glob is 60.8m/s.

To find the answer, we need to know about the orbital velocity a satellite.

<h3>What's the expression of orbital velocity of a satellite?</h3>
  • Mathematically, orbital velocity= √(GM/r)
  • G= gravitational constant= 6.67×10^(-11) Nm²/kg², M = mass of sun , r= radius of orbit

<h3>What's the orbital velocity of the satellite in a circular orbit with a radius of 1.45×10⁵ m around the planet Glob of mass 7.88×10¹⁸ kg?</h3>
  • Here, M= 7.88×10¹⁸ kg, r= 1.45×10⁵ m
  • Orbital velocity of the orbiting satellite = √(6.67×10^(-11)×7.88×10¹⁸/1.45×10⁵)

= 60.8m/s

Thus, we can conclude that the speed of the satellite orbiting the planet Glob is 60.8m/s.

Learn more about the orbital velocity here:

brainly.com/question/22247460

#SPJ1

6 0
2 years ago
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