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

Science key assessment 3 > Refraction/Reflection, Electromagnets, Space, Particle theory + Pressure, Static electricity > Flashcards

Flashcards in Refraction/Reflection, Electromagnets, Space, Particle theory + Pressure, Static electricity Deck (32):

What is the equation of pressure?

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


What is an electromagnet?

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


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

Gravitational attraction (force of gravity).


What happened once the sun was formed?

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.


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

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


How does an electric bell work?

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.


What are the three main uses of static electricity?

1. Photocopiers
2. Defibrillators
3. Spray painting


How does spray painting work?

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.


What is electricity explained by?



What is static electricity caused by?



Where are protons and neutrons found?

In the nucleus


What is charge measured in?

Coulombs (c)


One similarity between a comet and an asteroid...

They both orbit the sun.


Why does a white dwarf become a black dwarf?

Because the star has gone colder and has faded out.


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

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


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

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.


Define a black hole...

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


What is meant by refraction?

Light changes direction when it changes speed.


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

Light slows and the ray bends towards the normal.


What happens when the light ray leaves the glass?

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


The angle of reflection is always...

equal to the angle of incidence.


What is a red shift?

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.


What type of satellite is the earth's moon?



What is the force on the orbiting body?

Force of gravitational attraction between it and the larger body.


(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?

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.


Describe how a circuit breaker works... (2 marks)

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.


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

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


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

To move scrap vehicles using powerful electromagnets..


Describe how a scrapyard cane works... (2 marks)

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.


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

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.


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

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


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

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