y11 Triple Sciecnce

Electro Statics


Explain the following:

1) Nylon clothing crackles as you undress.
2) In dry weather, people walking on clean carpets may a shock if they touch a radiator
3) Passengers sliding off a car seat on to the ground sometimes get a shock
4) Petrol road tankers usually have a length of metal chain hanging down to touch the ground.
5) A rubbed balloon will stick to the wall for some time
6) A mirror or window polished by a dry cloth on a dry day may become dusty.
7) As sellotape is pulled of a roll it is attracted to your hand.
8) When spraying an object with paint, less paint is wasted if the object is charged
9) A TV screen becomes dusty
10) The amount of smoke leaving a factory can be reduced by placing a charged object in a chimney

y8 Joule

Weathering of the Elms

The oldest part of The Elms was built in 1735 for Sir Joseph Ayloffe. When it was built Acton was a small country village surrounded by fields.
How old is The Elms?
Describe the changes that have occurred in Acton since the Elms was built.

In contrast the Sports Hall was built in 1994.

We are going to look at the state of bricks in the two buildings.

The Elms

Some of the brickwork has been replaced so you must try and find an original brick.

Sketch the brick that you have chosen below.
Label features such as small holes and cracks. Is there any evidence of plant life such as moss or green/grey crusty lichens?
Look at other bricks, are they similar to the one you have drawn. Are there other features that you think are worth mentioning? Is the wear more noticeable parts of the building more exposed to the weather.

If there is time you can sketch another brick from the north side of the building.

The Sports Hall

Are any of the features seen in the bricks on The Elms visible in the bricks of the sports hall?

What reasons can you think of for the differences?
When The Elms was new do you think the bricks looked as they do now?
What could account for the change in surface of the bricks in the Elms?

Keywords

Chemical weathering, abrasion, smooth, rough, surface, cracks, flakes, breaking off, ice, snow, wind, sun, rain, heat, expansion, contraction

y12

The life cycle of stars

You are to produce a document to cover life cycle of stars of different masses.

You can email this to me, instead of printing.

Lots of information here http://www.astronomynotes.com/ and here http://bcs.whfreeman.com/universe6e/default.asp

Star birth

Perform a web search for giant molecular clouds, (The Eagle nebula and Orion Nebula are good examples). Insert a picture and add a caption.

“Giant molecular clouds are strung like pearls along the spiral arms of galaxies.”

Find a picture of a spiral galaxy. Hot blue stars are short lived so any we see are young. Note the blue light from the spiral arms.

Evidence of darker denser clouds can be seen in the horsehead nebula and other Barnard nebulae. Bok globules are even denser.

Protostars emit strongly in the infrared. You will find images at http://www.ipac.caltech.edu/Outreach/Edu/sform.html

Main Sequence.

There are many pictures of the sun and a search for Pleiades will give you and idea of a newly formed stellar cluster. Don’t forget the dim red ones.

The sun’s energy arises form nuclear fusion. Describe the fusion processes.

An animation may be found at this site in the chapter on the sun.

http://bcs.whfreeman.com/universe6e/default.asp

Choose animations and then complete list by chapter. There also animations on star birth you may view.

End States.

The sun will expand to a red giant before collapsing to a white dwarf (with a planetary nebula) you will find some good pictures of planetary nebulae.

Heavier stars will pass through the red giant stage before going supernova. Depending on its mass the core remnant will collapse into a neutron star or stellar black hole. The most famous supernova remnant is the crab nebula that contains a pulsar (a rapidly spinning neutron star). There are some excellent pictures of the crab and also x ray images of the neutron star which you should add to your account.

For obvious reasons there are no pictures of black holes but some excellent diagrams to look at.

Size and luminosity

Complete the table below.

Compare the other two stars with the sun by expressing their luminosities and radii in solar units.



Betelgeuse is slightly cooler than the Sun. Is it less luminous? How can you explain this?

Compare the luminosity of Alkaid with Betelgeuse. Which is larger? How then can you account for the difference in luminosity?

Alkaid is roughly 10 times the size of our sun and 3 times as hot. How much more luminous is it? How can you account for this?

Y13 Physics Homework

A loudspeaker connected to a signal generator emits a sound of frequency 500Hz and of constant amplitude in free air in the laboratory. Describe carefully how you would measure the wavelength of the progressive sound wave by a method that involves the formation of a stationary wave. (6 marks)

Identify two significant source of error in the experiment you have described.

State in each case

i. What steps you would take to minimise the errors
ii. An estimate of the uncertainty in the measurement associated with the error.
(6 marks)

Y11 Triple Science

Gravitational Potential Energy & Kinetic Energy

acceleration due to gravity = 9.8 m/s2

1. A car has a mass of 750 kg. Calculate its kinetic energy at the following velocities
(a) 10 m/s (b) 15 m/s (c) 20 m/s (d) 30 m/s (e) 35 m/s {NB 1 m/s =2 m p h}

2. (a) A car has a mass of 1000 kg. Calculate its KE at a velocity of 25 m/s.
(b) A train has a mass of 37 tonnes {1 tonne = 1000 kg}. If it also has a velocity of 25 m/s what is its kinetic energy ?

3. A woman has a mass of 65 kg.What is her GPE at the top of a 12 metre diving board ?

4. A cat has a mass of 6 kg. What is its GPE at the top of a tree that is 4.2 m above the ground ?

5. The Eiffel Tower is 300 m high. What is the GPE of a 100 g bird perched on the top of it ?

6. The Great Pyramid of Khufu (Cheops to the Greeks) is 146 m high. It is made of stones of mass 250 t. What is the GPE of the topmost stone ?

7. The Empire State Building is 449 m high(but this includes a 68 m TV mast).What is the GPE of a ball of mass 400 g at the top of the building (not the TV mast) ? If the ball is dropped over the side what will happen to the GPE ? What will be its speed at the instant before it hits the ground ? (Ignoring air resistance)

8. Olympus Mons is a volcano on Mars. It is 25 km high. What would be the GPE of a human of mass 50 kg on its summit ? (surface gravity = 0.38 that of Earth) Compare this with the same human standing on the summit of Everest 8534 m high.

9. The space shuttle has a mass of 80 t. Escape velocity (the velocity an object has to travel at in order to escape the earth's gravitational field) is 11 km/s. What is its KE at this speed? If all this KE is turned into GPE how high would it be ? What assumption do you have to make in your calculation.

How much energy would it take to accelerate the space shuttle to light speed (300 000 km/s). {This is not possible, also the equation you will use to calculate KE is not valid near the speed of light but it will do for this purpose} A nuclear power station produces around 500 MW
(500 000 000 J per second). How long would 100 power stations take to produce this amount of energy?
How feasible is travelling close to the speed of light?
The nearest star is about 4 light years away. How long would it take the space shuttle to get there at 11 km/s (22 000 mph)? {1 light year is the distance light will travel in 1 year}
How feasible is interstellar travel?

Y12 Homework

y13 Physics

Wave Equation- Problems


1. The range of sound frequencies which can be detected by a person is 17.0 Hz to 20.0 Khz. What is the corresponding range of wavelengths if the speed of sound in air is 340 ms?

2.
a) BBC Radio 4 broadcasts on a wavelength of 1.5 km what is it’s frequency?
b) What are the wavelengths of a TV station that transmits vision on 500 MHz and sound on 505 MHz?
c) What is frequency of yellow light of wavelength 0.6 mm? C= 3x108 ms-1

3. The floats of two men fishing in a lake from boats are 21m apart. A disturbance at a point in line with the two floats sends out a train of waves along the surface of the water so that the floats bob up and down 20 times per minute. A man in a third boat observes that when the float of one of his colleagues is on the crest of a wave when the other is in a trough and that there is one crest between them. What is the velocity of the wave?

4. A source of sound of frequency 550 Hz emits waves of wavelength 618 mm in air at 20°C. What is the velocity of sound in air at this temperature ? What would the wavelength of sound from this source be in air at 0°C (c=330ms-1 )

y12 Physics

Astrophysics Homework 1 ( from past paper)

Mark Scheme

Knowing that the angle at T is 10 deg or 1/2 T is 5 deg (1)
Use of Tan with any angle and using 10m as base (1)
114 m (1)

(i) (annual) parallax (1)
(ii) diameter of Earth's orbit around the sun (or on a diagram) (1)
(iii) (direction or background of more) distant stars (1)

Most stars are too distant (1)

Parallax is too small (to measure) (1) [not difficult]


This homework is now closed

Y11 Triple Science

Answers to Speed and Velocity

1. 32.25 m/s
2. 13.33 m/s
3. 15 m/s
4. 0.5 m/s
5. 39 600 m (39.6 km)
6. 612 km No the moon orbits the Earth
7. 9.4 x 10 15 s 1 year from the point of view of someone on Earth, but from your point of view no time has elapsed.
8. 8.57 million years
9. 7.5 s (yes it's Gazpacho)
10. 16.67 s
11. 9.09 s compared to 6.52 s. anaeorbic respiration cannot carry you 1500 m.
12. 0.476 s

The Steady Earth

i 1674.4 km/h 465 m/s Garvity, no as we have less far to travel. Theoretically zero.

ii 6822 km/h The tilt of the Earth

iii 1993.7 s (33 min)

iv 6000km but then I am quicker than you.

Y11

Answers to questions on velocity time graphs

5 (6 – 0)/(5 – 2) = 2 m/s2, (0 – 6 )/(12 –10) = –3 m/s2

6 Gradient = vertical increase/horizontal increase. For a velocity–time graph the vertical increase is the increase in velocity,and the horizontal increase is the time taken for this to happen.

7 The velocity has a positive value when the ball is going down.

8 The points where the sloping line crosses the time axis are where theball is at the top of its bounce.

9 The line would be getting steeper.

y13

y13

Phy 5 2004

y10

Answers to questions set in lesson.


1 Mercury (as well as extreme heat), Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
2 Mercury and Venus have
temperatures greater than that on the Earth.
3 Jupiter, Saturn, Uranus and Neptune – because they are ‘gaseous’ planets.
4 Venus: The planet has a thick highpressure atmosphere (enough to crush us), very high temperatures and its atmosphere has clouds of
sulphuric acid (so the rain would be acid!).
5 Europa has evidence of water – which is essential for life.
6 Reduced fuel costs as there is less effort to escape a planet’s or moon’s gravitational pull. It would also be cheaper to re-supply the hotels too, for the same reason.
7 Open-ended research question.

y10

Homework Answers


H5 Centripetal force and the
solar system
1 Rocky/circular orbit/much smaller than a planet
(less than 1000 km).
Any two. 2
Total 2
2 (a) Ellipse. 1
(b) When it is near the Sun. 1
(c) Frozen ice and rock. 1
Total 3
3 (a) The force of gravity 1
between Mars and the Sun. 1
(b) The force of gravity 1
between the comet and the Sun. 1
(c) The force of gravity 1
between the Moon and Earth. 1
Total 6
4 (a) Centripetal. 1
(b) (i) The tension in the string. 1
(ii) Friction between tyre and road. 1
(iii) The gravitational force between the
satellite and Earth. 1
Total 4
5 (a) Arrow from centre of the Moon pointing towards
the centre of Earth labelled force of Earth on
the Moon. 1
Arrow from centre of Earth pointing towards the
centre of the Moon labelled force of the Moon
on Earth. 1
(b) Both forces have the same size 1
and act in opposite directions. 1
(c) Answers involving the idea that the two forces
are not acting on the same body (e.g. Earth only
experiences one of the forces, the Moon
experiences the other force only). 1
Total 5

y11 chemistry homework

H9 Evaluating chemical
processes
1 (a) £83 799 2
Allow one mark for 235 . 200 + 5257 . 7
(b) (i) £17 007 1
(ii) £340.14 1
(iii) Any two from: transport cost/research and
development/depreciation/import/export
duty/taxes/loans/packaging/advertising. 2
(c) (i) £11 132 1
(ii) £445.28 1
(iii) The unit cost is less when more is made
per day. 1
Total 9
2 (a) A reaction that can change reactants into products
and the products back into the reactants. 1
(b) Correct data selected and plotted (only those at
100 atmospheres) 1
Suitable scale and labelled axes 1
Best-fit curve. 1
(c) Correct data selected and plotted (only those at
150°C) 1
Sensible scale and axes labelled. 1
Best-fit curve. 1
(d) Increases 1
(e) Decreases 1
(f) (i) Increases since there are more energetic
collisions/increases because there are more
collisions per second. 1
(ii) Increases because there are more collisions
per second. 1
Total 11

Y13 Physics phy6 2006

Y13

Markscheme for Synoptic paper here.

http://www.edexcel.org.uk/VirtualContent/48956/GCE_Physics_6736_epen_Exemplar_Markscheme.pdf

Y12 Homework on Radioactivity

The formatting for the tables is slightly askew but you can work it out.

Nuclear Physics

1. Radon has a proton number of 86 and a nucleon number of 220. It emits an α-particle to become Thorium A (polonium), which emits another α particle to become Thorium B (radioactive lead). Thorium B then emits a β-particle to become Thorium C (bismuth). What is (a) the proton number and (b) the nucleon number of Thorium C?

2. When a Boron nucleus 105B is bombarded with a neutron a nucleus of Lithium 73Li, is produced, together with another particle. What are the proton number, the nucleon number and the name of this particle?

3. A ’snap-shot’ photograph of a cloud chamber shows 40 well-defined alpha particle tracks. A second ’snap-shot’ taken 2 min later shows only 10 tracks. What is the half-life of the alpha source?

4. A lead container has a narrow slit and sources inside emit α, β and γ rays. A powerful magnetic field is applied. Draw a labelled sketch to show what happens – the rays emerge vertically upwards in the plane of the paper and the field is applied so that the flux passes at right angles into the plane of the paper.

5. A Geiger-Muller tube connected to a rate meter is held near a radio-active source. The corrected count rate (allowing for background count) is 400 Bq. 40 min later the corrected count rate is 25 Bq. What is the half-life of the source?

6. A rate meter records a background count rate of 2 Bq. When a radioactive source is held near the count rate is 162 Bq. If the half-life of the source is 5 min, what will the recorded count rate be 20 min later?

7. A patient suffering from cancer of the thyroid gland is given a dose of radioactive iodine 131, with a half-life of 8 days, to combat the disease. He is temporarily radioactive and his nurses must be changed regularly to protect them. If his radioactivity is initially 4 times the acceptable level, how long is it before the special nursing rota can be dropped?

8. An experiment to determine the half-life of a radioactive gas using a Geiger-Muller tube and a rate meter gave the following results:

Background count rate; 1 Bq
Time/s
0
20
40
60
80
100
120
140
160
Recorded count rate/Bq
71
55
43
34
26
20
16
12
10
Plot a graph and estimate the half-life of the gas.

9. Thoron gas was introduced into a ’decay chamber’ attached to a pulse electroscope. The times at which successive pulses occurred were recorded, giving the following results:
Pulse number
1
2
3
4
5
6
7
8
9
10
Time/s
8
17
28
40
55
75
100
135
200
500
Draw a ’pulse number-time’ graph and estimate the half-life of Thoron.

10. An ionisation chamber was connected to a pulse electroscope and an alpha source held near it. Beyond a certain distance no pulses were produced. For smaller distances the pulse rate varied as follows:
Distance from source /cm
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Number of pulses per min
100
90
68
44
26
14
8
4
1

Plot a graph and estimate the range of the alpha particles.

PHY 5 2006 Markscheme