Some hard some easy let's get a mark scheme compiled
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)
(The same comment can be made about the £40 per square meter one with only 10% increase and 8x more expensive)
23. Control Variable: (1)
1. The volume of the containers are the same
2. Airflow in the room
3. Temperature of the surroundings
4. Anything else about the beaker being the same ie width thickness material
24. Data logger vs Thermometer: (2)
1. Higher resolution (decimal points) (Aka more accurate)
2. Displays the numbers so more precise as it reduces estimation from reading the thermometer
3. Creates a graph
4. Updates quicker
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)uction , convection.