⭐️W6 L1 - Powering stars - The power of stars

Question 1

How many times larger than the Earth is the Sun’s diameter?

Answer 1

About 109 times larger

Question 2

Who discovered the relationship between period & luminosity in Cepheid variable stars?

Answer 2

Henrietta Swan Leavitt

Question 3

In 1920, who published a paper describing fusion within stars?

Answer 3

Sir Arthur Eddington

Question 4

What does the atomic number of an atom refer to?

Answer 4

The number of protons in its nucleus

Question 5

What particle stabilises the nucleus?

Answer 5

The neutron

Question 6

What is the name for the form of hydrogen with one proton and one neutron?

Answer 6

Deuterium

Question 7

What is the electrostatic force?

Answer 7

The short range attraction or repulsion between particles due to their electric charge

Question 8

What’s another name for the electrostatic force?

Answer 8

The Coulomb Force

Question 9

What is the name for the repulsive process caused by electric charge?

Answer 9

Coulomb repulsion

Question 10

What force holds protons together if they get close enough?

Answer 10

The strong nuclear force

Question 11

How big is a femtometer in scientific notation?

Answer 11

1 x 10⁻¹⁵ metres

Question 12

What is nuclear fusion?

Answer 12

The process of overcoming electrostatic repulsion between protons to join atomic nuclei and make new atoms.

Question 13

How many Hydrogen atoms do you need to fuse to make one Helium atom within a star?

Answer 13

Four, which gives one Helium atom and two Hydrogen atoms

Question 14

What is the temperature of the surface of the sun (in Kelvin)?

Answer 14

About 5,000 Kelvin

Question 15

What is the temperature at the core of the sun?

Answer 15

About 15 million K

Question 16

What is the density of the Sun at the core compared with water?

Answer 16

About 40 times that of water

Question 17

How much Hydrogen does the Sun fuse per second?

Answer 17

6 x 10⁻¹¹ kg/s

Question 18

What is the mass of the Sun

Answer 18

2 x 10³⁰ kg

Question 19

What are the two opposing expansion and contraction forces in the Sun?

Answer 19

Contraction from gravity, expansion from the energy of fusion

Question 20

What is the balance of expansion and contraction forces in the Sun called?

Answer 20

Hydrostatic equilibrium

Question 21

Moving out from the core of the Sun, what is the first zone of energy transfer called?

Answer 21

The radiative zone

Question 22

What zone is found outward from the radiative zone in the sun?

Answer 22

The convective zone

Question 23

Roughly how big is a convection cell on the surface of the Sun?

Answer 23

About the size of Texas

Question 24

When the Sun’s high temperatures strip electrons from atoms what does it produce?

Answer 24

Plasma

Question 25

What produces the Sun’s magnetic field?

Answer 25

Circulating plasma

Question 26

How long between solar minima?

Answer 26

11 years

Question 27

At a solar minimum what shape are the Sun’s magnetic fields?

Answer 27

Aligned like a bar magnet

Question 28

At solar maximum, what shape are the Sun’s magnetic fields?

Answer 28

Messy

Question 29

Are there more sunspots at solar minima or maxima?

Answer 29

Solar maxima

Question 30

Are sunspots hotter or cooler than the rest of the surface of the Sun?

Answer 30

Cooler

Question 31

What holds plasma in place to cool down at the position of sunspots?

Answer 31

The Sun’s magnetic fields

Question 32

What might generate the cyclical nature of solar cycles?

Answer 32

Feedback loops between magnetic fields and plasma

Question 33

Why are bigger stars hotter?

Answer 33

The expansion and contraction forces are greater because of the larger size