Midterm 1 Key Facts Flashcards

1
Q

What do lightyears mean about how we view the universe

A

We can see ‘back in time’

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2
Q

What is a light-year?

A

The distance that it takes for light to travel in one year

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3
Q

What is an Astronomical Unit (AU)?

A

The average distance between the earth and the sun

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4
Q

How fast is the speed of light in a vacuum?

A

3x10^8 meters per second

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5
Q

What is a photon?

A

A piece/particle of life

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6
Q

What does a longer frequency mean?

A

A longer wavelength

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7
Q

What does a longer wavelength mean?

A

Lower energy

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8
Q

At what temperature do stars appear blue?

A

Over around 10,000 Kelvin

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9
Q

At what temperature do stars appear red?

A

Below around 3,000 Kelvin

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10
Q

What is the surface temperature of the Sun?

A

Around 5,800 Kelvin

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11
Q

What is nuclear fusion?

A

The process of combining lightweight nuclei into heavier nuclei, releasing enough energy to supports stars against collapse from gravity

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12
Q

What does it mean when an atom is ionised?

A

when it loses/gains one or more electrons

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13
Q

What is the defining difference in different chemical elements?

A

They have different numbers of protons

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14
Q

Different isotopes have different numbers of what?

A

Neutrons

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15
Q

What is temperature?

A

The measurement of the average speed of the particles?

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16
Q

How old is the earth?

A

4.6 billion years old