Physics P2 and P3

1. What is Nuclear Fission?

2. Name the two fissionable isotopes. 

3. What must happen for Fission to occur?

4. What then happens?

1. The process of an atomic nucleus splitting. 

2. Uranium- 235 and Plutonium -239 

3. The uranium-235 or plutonium-239 nucleus must absorb a neutron.

4. The nucleus splits in to two smaller nuclei and two or three neutrons and energy is released.  The neutrons then go on to produce further fissions, creating a chain reaction. 

1. What is Nuclear fusion?

2. Where does fusion happen?

3. During Nuclear fusion _____ is released in stars?

4. What are the control rods made out of for this process?

5. What do control rods do?

6. How many protons and neutrons does an alpha particle have?

7. What is a beta particle?

8. Neutrons have a relative mass of ___ and an overall charge of what?

9. State some disadvantages of a Nuclear power reactor.

10. Name two natural sources of background radiation

11. Name an artificial source of background radiation. 

1. When two atomic nuclei join together to form 1 single, larger nucleus.

2. In stars.

3. Energy.

4. Boron 

5. They absorb neutrons so they cannot go on to spilt more uranium.

6. 2 protons and 2 neutrons 

7. A high speed electron from the nucleus. 

8. Relative mass of 1. Overall 0 charge.

9. The waste is radioactive, plutonium waste is used in bombs, waste is radioactive for a very long time, the reactor itself becomes radioactive due to bombardment with the neutrons.         10. Cosmic rays and rocks.     11. Nuclear power station.

1. What is the equation for working out moments?

2. What is the unit of a moment?

3. Moments can be increased by...?

4. Define effort, load and pivot. 

1. Moment = force (N)  x perpendicular distance from the pivot (M) 

2. Nm (Newton meters) 

3. Using a larger force or a longer spanner etc. 

4. Effort; The force applied by a person, Load; what is trying to be moved. Pivot; the point at which the spanner or crowbar turns. 

1. What does centre of mass mean?

2. Give two features which make an object more stable.

3. Using the term 'line of action of the weight' explain why a stable object will not fall over?

4. Using the term 'resultant moment' explain why a stable concerte mixer doesn't fall when given a small push.

5. Weight = force due to ________?

6. List factors that affect the force due to gravity. 

7. Weight changes depending on _______?

8. What is the equation for weight?

1. Centre of mass of an object is where its weight is thought to be the most concentrated. 

2. Centre of mass low to the floor, and a wider base for better stability. 

3. Because its line of action of the weight will stay within the base of the mixer. 

4. Becuase the resultant moment returns the mixer to its original position.

5. Gravity 

6. Distance and increase of mass.

7. Position.

8. Weight = Mass x Gravity. 

1. Name all the planets, starting from closest to the sun.

2. What does AU stand for?

3. Planets move in an _______ orbit.

4. What does elliptical mean?

5. What is meant by 'period of a planet' ?

6. What is the relationship between a planets distance from the sun and its period?

7. What force provides the centripetal force to keep planets in their orbits?

8. What is the name of the galaxy which contains the solar system?

9. The universe is made up of _____ of galaxies.

1. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto

2. Astronomical Unit. 

3. Elliptical orbit. 

4. Orbiting the sun in a slightly squashed circle. 

5. How long it takes to orbit the sun. 

6. Further away from the sun = Larger period. 

7. Gravity. 

8. Milky way 

9. Billions. 

1. What will happen if a satellites speed is too slow?

2. What will happen if a satellites launch speed is too high?

3. The further away a satellite is from Earth, the _______ the travelling speed.

4. Why is does this happen?

5. What are satellites in a polar orbit good for is their orbit high or low and why ?

6. Communications satellites remains above the same place of the Earth’s surface constantly. We call this a  _________ orbit. 

7. They travel the _____speed as the earth spins on its axis. 

8. Equatorial satellites are good for...? 

9. When a comet approaches the sun the force of gravity on it...?

1. It will fall to the ground. 

2. It will fly off into space. 

3. Slower. 

4. Because of the gravitational pull of the earth on the satellite.

5. Weather monitoring, low orbit to see as much detail of the earth as possible. They go past the poles so see the entire earth. 

6. Equatorial orbit 

7. Same.

8. Communications, Televisions and GPS 

9. Increases. 

1. A star forms from clouds of ______ and _____.

2. This ______ joins together under its own ____________ force and the clouds merge together. 

3. They become denser and denser until they form a p________.

4. Why does a star remain stable ?

5. What happens to a star after it reaches the red giant stage?

6. How are atoms of elements formed in a star?

7. How were very heavy element like gold formed?

8. Explain how, and when, atoms of different elements may be distributed throughout the universe.

1. Gas and dust

2. Matter, gravitational. 

3. Protostar 

4. From hydrogen fusion in the core, stars radiate energy and can do so until it runs out of hydrogen nuclei to fuse together. (this makes it stable) 

5. No more radiation is released, and the star collapses in on itself. During collapsion, it heats up again, and turns from red, to yellow to white – it becomes a white dwarf. 

6. From fusion of hydrogen nuclei. 

7. From fusion of other lighter elements during a supernova.

8. From a supernova when the star dies. 

1. Why is iron used in the core of a transformer?

2. Why are the transformers coils made of insulated copper wire?

3. Step-up transformers take the p.d. from a power station up to the Grid p.d. So step down transformers do what?

4. Why is the core laminated?

5. Why do transformers only work with an Alternating current?

6. How does a transformer work? LEARN! 

1. Because it needs to create a magnetic field ( iron = magnetic)

2. To stop short circuiting. 

3. Take the grid p.d and step it down to mains voltage. 

4. To cut out induced current in the iron layers. 

5. Because a direct current does not induce alternating magnetic fields and so an alternating secondary voltage cannot be produced.

6. AC voltage into primary coil 

Creates a changing magnetic field in the iron core

And hence a magnetic field in the secondary coil 

Induces an alternating voltage on the secondary coil. 

and hence alternating current in secondary coil. 

1. What is the equation for momentum?

2. The momentum before = ?

3. The momentum of a moving object is __ if no forces act on it. 

4. If impact time is made shorter, what happens to to impact forces?

5. What is the equation for kinetic energy?

6. What is the equation for work?

1. Momentum = mass x velocity. 

2. The momentum after 

3. Zero 

4. They will be increased. 

5. Kinetic energy = 1/2  (mass x speed²)

6. Work = force x distance ( I remember this as wok fried duck. ) 

1. A perspex rod becomes __ charged when rubbed with a dry cloth

2. A polythene rod becomes __ charged when rubbed with a dry cloth

3. Name the particles that have moved to make this happen

4. What is an ion?

1. + 

2. -

3. Electrons 

4. An atom that has gained or lost electrons