Sorry. It asked for TEMPERATURE CHANGE not the actual temp. It was 22oC

Well ****. This is what I thought It asked anyway? It gave SHC, what we needed to find out what the temperature difference. and the difference was 22. From my calculations anyway??

I put 22 degrees celsius as well. So was it 22 or 78?!

Reply 69

JamesHare

No it didn't, you're wrong. :-)

Reply 70

username2579951

Original post by amaladam21

sorry no, it asked for the temperature after 2 hours, you needed to work out the difference then minus it from 100. The answer was 78

are you kidding me omfg i put 78 but changed it to 22 ughhhhhh

Reply 71

elphjoho

Original post by Connor2909

Reduces energy transfer by conduction and convection

I only put transfers energy by conduction and explained. Will i still get the marks?

Reply 72

Mastabator123

I ****ed the six mark question.

Reply 73

HeimIX

Original post by Imogenxmoore

Yeah I did too, but i rounded it to 6.42 as it as a reoccurring decimal

Lol that's wrong, in physics there are no recurring decimals, you had to press sd on your calc to get another value xD

Reply 74

caseyforbes11

I'm scared now haha, I wrote 78 degrees as I thought you did 100-22 which gives you 78 degrees

Reply 75

11alexandru-kore

For the speed I got 0.34m/s because the formula is speed(m/s)=frequency(Hz)x wavelength(m)
so its 0.0136m X 25Hz=0.34m/s?

Reply 76

dontgetittwisted

Would echo by itself be ok for the first question

Reply 77

RubiksNinja

Original post by dontgetittwisted

Would echo by itself be ok for the first question

Yeah i am pretty sure it would be :smile:

Reply 78

yoyo1999

I wrote that decreasing the volume would not affect the experiment, is that right??

Reply 79

kad126

AQA Physics Mark Scheme

1. Frequency determines pitch (1)
2. Echo (1)
3. The sound waves bends (1)
4. Waves length larger/equal to than the bat (1)
5. Longitudinal wave: Vibrates/oscillations parallel (90°) to the energy transfer (2)
6. Communications of:
1. Infra red - remote controls (1)
2. Microwaves - mobile phones/satellite (1)
7. Both microwaves and infrared radiation: (2)
1. Transverse waves
2. Travel at the speed of light in a vacuum
8. CMBR (1)
9. Provides evidence for the big bang theory (1)
10. It's not economical because: (2)
1. Small village (very few people)/remote location so connecting to the national grid is not economically viable/profitable
2. Micro generation has a higher efficiency of generation
3. They live on mountains so cables would need to travel very far to connect to them (lots of energy loss)
11. Wind turbines vs Hydroelectric generator: (6)
1. Wind more expensive (£50,000) than hydroelectric (£20,000)
2. Wind generated the most (10 KW) than hydroelectric (8KW)
3. Hydroelectric provides constant energy so more reliable whereas wind varies so not as reliable.
4. Hydroelectric generators ruin the habitat.
5. Wind turbines visual pollution/eye sore.
12. The heat escapes into the surrounding so not all the heat is received by the food/very little useful energy. (2)
13. Fins - increased surface area so more particles are exposed to to heat (1)
14. Black metal - absorbs infra red radiation so heats better/metal is a good conductor of heat (1)
15. As you increase the temperature, the rate of which it emits infra-red radiation will increase (because of a bigger temperature increase) (2)
16. Vacuum in kettle prevents heat loss through conduction and convection (2)
17. Temp. change = 46,200 / 0.5x4,200 = 22, New temp. = 100-22 = 78° (3)
18. Useful energy = 0.15 x 3.2 = 0.48KJ (2)
19. P = E/t = 46,200 / 2 x 60 x 60 = 6.4 W (2)
20. France would continue using nuclear power because: (2)
1. It's the cheapest the generate
2. It provides the largest amount of energy (and extra could he sold for profits)
21. Disadvantages of nuclear stations: (2)
1. Radioactive waste
2. Expensive to decommission
3. Very dangerous, if explosions occur, people could die/get serious illnesses
22. When the efficiency increases by just 5%, it costs an extra £17.50 to manufacture, which is expensive and eventually not be economically viable/profitable. (2)
23. Control Variable: (1)
1. The volume of the containers are the same
2. Airflow in the room
3. Temperature of the surroundings
24. Data logger vs Thermometer: (2)
1. Higher resolution (decimal points)
2. Displays the numbers so more precise as it reduces estimation from reading the thermometer
3. Creates a graph
25. 20-13.25 / 100 = 0.0675 °/s (2)
26. They all decreased at a decreasing rate (1)
27. A because it decreased in temperature the least (2)
28. Decreasing the volume increases the surface area so more evaporation meaning it will lose temperature quicker. (1)
29. Particles in the water with the highest kinetic energy are able to break the intermolecular forces between the particles/escape the liquid thus reducing the overall kinetic energy of the water. This causes it to cool down. (3)
30. Factors of heat transfer to coffee: (2)
1. The amount of energy the heater receives
2. The temperature of the room
31. The heater heats the bottom of the glass, making the particles vibrate/gain kinetic energy, which pass on to the neighbouring particles until the whole bottom of the glass is heated. (3)
32. Particles near the heater gain kinetic energy so they become less dense and rise. They displace the cooler, more dense particles which then sink. These then gain kinetic energy, decrease density and rise and this continues as convection currents. (4)

60/60

Sorry for the **** format, on my phone