paper 2- wrong q's

Question 1

two differences between light and sound waves (2):

Answer 1

1. light waves are transverse, sound waves are longitudinal
2. light waves travel faster than sound waves

Question 2

describe how neutrons released in fission can cause a chain reaction (2):

Answer 2

1. neutrons released by uranium-235
2. neutrons absorbed by another nucleus
3. nucleus splits, releasing more neutrons

Question 3

explain how transformers are useful in the large-scale transmission of electricity (5):

Answer 3

1. step up transformer used before transmission
2. voltage in increased before transmission
3. current is reduced before transmission
4. less heating in transmission cables
5. less energy wasted in transmission cables
6. step down transformer used after transmission
7. voltage is decreased after transmission for safety

Question 4

name a piece of apparatus that could be used to measure the weight of the metal block (1):

Answer 4

1. balance
2. newton meter

Question 5

explain what is meant by background radiation (2):

Answer 5

1. always present everywhere
2. radon gas

Question 6

suggest why you can only be in a certain area of high background radiation for a short amount of time (3):

Answer 6

1. excessive exposure can be harmful
2. dosage is higher
3. increased risk of cancer
4. radiation is increased

Question 7

explain how cosmic microwave background radiation (CMBR) supports the Big Bang theory (2):

Answer 7

1. CMBR appears to be the same in all directions
2. which implies that all parts of the universe were in contact a long time ago

Question 8

explain the operation of a step down transformer (4):

Answer 8

1. step down means secondary voltage is less than primary voltage
2. current in primary coil produces a magnetic field
3. the current is changing
4. causing a changing magnetic field in the core
5. the core strengthens the magnetic field
6. the secondary coil experiences a changing magnetic field
7. which induces a voltage in the secondary coil

Question 9

state what is meant by the term absolute magnitude (2):

Answer 9

1. a measure of brightness
2. a star would be at a standard distance (10 perspecs)

Question 10

explain how a plastic tube becomes positively charged (2):

Answer 10

1. electron transfer
2. loss of electrons

Question 11

explain why there is a wire connecting a metal mast to the earth (3):

Answer 11

1. electrons move through wire
2. as they move through, they are attracted to metal mast
3. makes metal mast neutral

Question 12

describe how the student could use their apparatus to help determine the specific heat capacity of a substance (5):

Answer 12

1. measure current and voltage to work out power
2. use ammeter and voltmeter
3. measure temperature increase and time taken
4. find total energy E=Pt
5. measure mass
6. use a balance

Question 13

explain what happens during nuclear fusion (3):

Answer 13

1. creation of a large nucleus from small nuclei
2. resulting in a loss of mass
3. and release of energy

Question 14

explain two conditions needed for nuclear fusion (4):

Answer 14

1. high temperature
2. higher kinetic energy
3. high pressure
4. so that nuclei are more likely to collide

Question 15

describe how a student could determine the specific heat capacity of water (6):

Answer 15

1. measure mass of water (mass of water and cup - mass of cup)
2. use a balance
3. time measured on a stopwatch
4. find temperature change
5. use equation energy supplied= voltmeter reading x ammeter reading x time
6. repeat whole experiment and calculate averages
7. stir water constantly
8. plot a temperature versus time graph
9. find gradient

Question 16

explain how a transformer works (6):

Answer 16

1. steps up or steps down the voltage
2. current in primary coil produces a magnetic field
3. current is changing/ alternating
4. causing a changing magnetic field in the coil
5. the core strengthens the magnetic field
6. iron is a soft magnetic material
7. field lines interact with secondary coil
8. which induces a voltage in the secondary coil
9. transformer won’t work with dc

Question 17

how could the primary coil of the transformer be changed to increase output voltage (1)?

Answer 17

less turns

Question 18

explain whether or not the energy in the kinetic store of the particles changes when the sample is changing state (3):

Answer 18

1. kinetic energy stays constant
2. temperature stays constant during state change
3. speed of particles does not change

Question 19

state the principal of conservation of momentum (1):

Answer 19

momentum before event= momentum after event