Physics Astrophysics

Question 1

What is the unit of mass?

Answer 1

kilogram (kg)

Question 2

What is the unit of distance?

Answer 2

metre (m)

Question 3

What is the unit of speed?

Answer 3

metres per second (m/s)

Question 4

What is the unit of acceleration?

Answer 4

metres per second squared (m/s12)

Question 5

What is the unit of force?

Answer 5

newton (N)

Question 6

What is the unit of time?

Answer 6

second (s)

Question 7

What is the unit of gravitational field strength?

Answer 7

newton per kilogram (N/kg)

Question 8

What is the universe?

Answer 8

A large collection of billions of galaxies

Question 9

What is a galaxy?

Answer 9

A large collection of billions of stars held together by gravity

Question 10

Which galaxy is our solar system in?

Answer 10

The Milky Way galaxy

Question 11

What does gravitational field strength (g) mean?

Answer 11

Force per unit mass

Question 12

Why is gravitational field strength different on different planets?

Answer 12

Different masses and radii

Question 13

Why is Earth’s gravitational field stronger than the Moon’s?

Answer 13

Earth has more mass

Question 14

What happens to weight if g decreases?

Answer 14

Weight decreases

Question 15

What force keeps moons in orbit around planets?

Answer 15

Gravitational force

Question 16

What force keeps planets in orbit around the Sun?

Answer 16

Gravitational force

Question 17

What force keeps artificial satellites in orbit around Earth?

Answer 17

Gravitational force

Question 18

What force keeps comets orbiting the Sun?

Answer 18

Gravitational force

Question 19

How do planet orbits compare to comet orbits?

Answer 19

Planets are nearly circular, comets are highly elliptical

Question 20

What do moons orbit?

Answer 20

Planets

Question 21

What do planets orbit?

Answer 21

The Sun

Question 22

Why do comets develop a tail near the Sun?

Answer 22

Ice vaporises forming gas and dust

Question 23

What is the equation for orbital speed?

Answer 23

v = 2nr / T

Question 24

What does v represent in orbital motion?

Answer 24

Orbital speed

Question 25

What does r represent in orbital motion?

Answer 25

Orbital radius

Question 26

What does T represent in orbital motion?

Answer 26

Time period

Question 27

How does orbital speed change if radius increases (same T)?

Answer 27

Speed increases

Question 28

How can stars be classified?

Answer 28

By colour

Question 29

What colour are the hottest stars?

Answer 29

Blue

Question 30

What colour are cooler stars?

Answer 30

Red

Question 31

How is star colour related to temperature?

Answer 31

Hotter stars are bluer, cooler stars are redder

Question 32

What colour is the Sun?

Answer 32

Yellow

Question 33

What is the first stage in the life of a Sun-like star?

Answer 33

Nebula

Question 34

What is a nebula?

Answer 34

A cloud of gas and dust where stars form

Question 35

What happens during the main sequence stage?

Answer 35

Hydrogen fuses into helium

Question 36

What does a Sun-like star become after main sequence?

Answer 36

Red giant

Question 37

What is the final stage of a Sun-like star?

Answer 37

White dwarf

Question 38

What supports a white dwarf against collapse?

Answer 38

Electron pressure

Question 39

What does a massive star become after the main sequence?

Answer 39

Red supergiant

Question 40

What happens when a massive star explodes?

Answer 40

Supernova

Question 41

What objects can form after a supernova?

Answer 41

Neutron star or black hole

Question 42

When does a black hole form?

Answer 42

When the core collapses completely