Refraction/Reflection, Electromagnets, Space, Particle theory + Pressure, Static electricity

Question 1

What is the equation of pressure?

Answer 1

Pressure= Force(N) divided by Area (m squared)
Example = 12000N divided by 3.0 m squared = 4000 Pa

Question 2

What is an electromagnet?

Answer 2

A solenoid in which the insulated wire is wrapped around an iron bar (the core).

Question 3

Write the force that can cause dust and gas particles to attract each other…

Answer 3

Gravitational attraction (force of gravity).

Question 4

What happened once the sun was formed?

Answer 4

Once the sun was formed, its heat evaporated ice and drove gas away from the inner solar system, leaving rocks behind. The rocky planets formed near the sun and the gas giant planets formed further away.

Question 5

Give three ways that the strength of an electromagnet can be increased by…

Answer 5

1. More coils
2. Increase current
3. Add iron core

Question 6

How does an electric bell work?

Answer 6

When an electric bell is connected to a battery, the iron armature goes toward the electromagnet. The make-and-break switch opens and the electromagnet turns off. The iron armature springs back and the make-and-break switch closes again, the cycle repeats itself.

Question 7

What are the three main uses of static electricity?

Answer 7

1. Photocopiers
2. Defibrillators
3. Spray painting

Question 8

How does spray painting work?

Answer 8

Paint is positively charged. The paint spreads out because the charges repel each other. This is because the object (for example a bike) is negatively charged and when the paint is applied it stays on the object as the two charges attract.

Question 9

What is electricity explained by?

Answer 9

Electrons

Question 10

What is static electricity caused by?

Answer 10

Friction

Question 11

Where are protons and neutrons found?

Answer 11

In the nucleus

Question 12

What is charge measured in?

Answer 12

Coulombs (c)

Question 13

One similarity between a comet and an asteroid…

Answer 13

They both orbit the sun.

Question 14

Why does a white dwarf become a black dwarf?

Answer 14

Because the star has gone colder and has faded out.

Question 15

Where did the energy that heated the stars come from? (1 mark)

Answer 15

The energy that heated stars came from nuclear fusion, which involves two atomic nuclei joining together.

Question 16

What will happen to the sun after its present stage? (3 marks)

Answer 16

It will turn into a red giant once all the Hydrogen has fused to helium and made elements up to iron in its core.
It will then get rid of the layer of dust surrounding it (planetary nebula) and turn into a white dwarf.
Before it cools down and becomes a black dwarf.

Question 17

Define a black hole…

Answer 17

A region in space which has a gravitational field so intense that no matter or radiation can escape.

Question 18

What is meant by refraction?

Answer 18

Light changes direction when it changes speed.

Question 19

What happens when a ray of light goes through a block of glass?

Answer 19

Light slows and the ray bends towards the normal.

Question 20

What happens when the light ray leaves the glass?

Answer 20

The light speeds up and the ray bends away from the normal.

Question 21

The angle of reflection is always…

Answer 21

equal to the angle of incidence.

Question 22

What is a red shift?

Answer 22

A red shift is when the wavelengths of the waves are increased. The light waves are stretched out if a galaxy is moving away from you.

Question 23

What type of satellite is the earth’s moon?

Answer 23

Natural.

Question 24

What is the force on the orbiting body?

Answer 24

Force of gravitational attraction between it and the larger body.

Question 25

(In relation to electromagnets) what happens when a current is passed along a wire?

What happens due to this?

What happens when the current is switched off?

Answer 25

A magnetic field is created around the wire.

The magnetic field of the wire magnetises the iron bar.

The iron bar loses most of its magnetism.

Question 26

Describe how a circuit breaker works… (2 marks)

Answer 26

A circuit breaker is a switch in series with an electromagnet. The switch is held open by a spring. When the current is too large, the switch is pulled open by the electromagnet and it stays open until it resets manually.

Question 27

State the purpose of a circuit breaker… (2 marks)

Answer 27

The purpose of a circuit breaker is to protect an electrical circuit from damage caused by excess current,

Question 28

State the purpose of a scrapyard cane… (2 marks)

Answer 28

To move scrap vehicles using powerful electromagnets..

Question 29

Describe how a scrapyard cane works… (2 marks)

Answer 29

The steel frame of a vehicle sticks to the electromagnet when a current passes through the coil of the electromagnet. When the current is switched off, the vehicle frame falls of the electromagnet.

Question 30

Describe the big bang theory of the universe (2 marks)

Answer 30

The big band theory states that after the universe exploded suddenly (big bang) from a very small and extremely hot and incredibly dense region and began to expand. Space, time and matter was created in the big bang.

Question 31

Explain why many astronomers did not support the big bang theory when it was first proposed…

Answer 31

Originally, people supported the Steady State theory. This theory stated that galaxies are being pushed apart by matter entering the universe through white holes.

Question 32

Explain the significance of the discovery of cosmic microwave background radiation…

Answer 32

Cosmic microwave background radiation can only be explained by the big bang theory meaning the Steady State theory was no longer relied upon.