Paper 2 Required practicals

Question 1

Elasticy PAG - Describe a suitable method

Answer 1

Hang a spring off a clamp stand

Measure the original length of the spring

Add a 1 N weigth and measure the final length of the spring with a ruler

Calcualte the extension (final length - original length)

Repeat for weights 2, 3, 4, 5 and 6 N

Question 2

Elasticy PAG - State the variables and whether they are continuous, discrete or catergoric

Answer 2

Independent - Weight (continuous)

Dependent - Extension (continuous)

Control - Spring constant (continuous)

Question 3

Elasticy PAG - What type of graph should you draw? Why?

Answer 3

Line - both variables are continuous

Question 4

Elasticy PAG - Describe the expected results

Answer 4

Forces is directly proportional to extension as long as the elastic limit hasnt been passed.

The graph should be a straight line through the origin

Question 5

Elasticy PAG - What is the main cause of error and how can it be reduced?

Answer 5

Parallax error not having your eye level with the spring when measuring its extension.

Reduce this my placing a wooden splint horizontally at the bottom of the spring.

Question 6

Elasticy PAG - Describe a suitable risk assessment

Answer 6

Clamp stand may topple - this could fall and hurt your foot - place a counter weigth on the base of the clamp to stop it toppling

Question 7

Elasticy PAG - Describe elastically deformed

Answer 7

The object will return to its original length when all forces are removed

Question 8

Elasticy PAG - Describe inelastically deformed

Answer 8

An object wont return its original length once all forces are removed, it has been permanently stretched.

Question 9

Elasticy PAG - State Hooke’s law equation

Answer 9

Force (N) = Spring constant (N/m) x extension (m)

Question 10

Elasticy PAG - how can the spring constant be found from a graph of force against extension

Answer 10

From the gradient

Question 11

Newton’s second law PAG - state the relevant equation

Answer 11

Resultant Force (N) = mass (kg) x acceleration (m/s²)

Question 12

Newton’s second law PAG - Describe a suitable method

Answer 12

Attached a piece of card of known length to a trolley.

Attached some string to the trolley running over a pulley.

Place a 1 N weigth on the end of the string and allow it to accelerate the trolley through two light gates.

Use the light gates to measure the acceleration of the trolley

Repeat for 2, 3, 4, 5 and 6 N

Question 13

Newton’s second law PAG - State the variables and whether they are continuous, discrete or catergoric

Answer 13

Independent - Resultant force (continuous)

Dependent - Acceleration (continuous)

Control - mass of trolley (continuous), Material of surface (discrete)

Question 14

Newton’s second law PAG - State the expected results

Answer 14

As resultant force increases the acceleration will increase. They are directly proportional to each other so the graph should be a straight line through the origin.

Question 15

Newton’s second law PAG - Describe a risk assessment

Answer 15

Falling masses - could land on your feet - stand away from the experiment

Question 16

Newton’s second law PAG - If the resultant force was kept constant but the mass of the trolley was increased what results would you expect?

Answer 16

As mass of the trolley increases the acceleration will decrease, they are inversley proportional to each other.

Question 17

Newton’s second law PAG - What type of graph should you draw? Why?

Answer 17

Line - both variables are continuous

Question 18

Newton’s second law PAG - How can a light gate measure velocity?

Answer 18

Tell the data loger the length of card (distance)

The light gate will measure the time the card blocks the laser.

Velocity = distance / time

Question 19

Newton’s second law PAG - How can two light gate measure acceleration?

Answer 19

Light gate 1 measures initial velocity

Light gate 2 measures final velocity

Light gate measure the time between light gates

acceleration = change in velocity / time

Question 20

Absorption PAG - Describe a suitable method

Answer 20

Attache temperature probes to each side of the Leslie cube using elastic bands.

Attach the temperature probes to a data logger.

Fill the Leslie cube with boiling water,

Measure and record the starting temperature.

Measure and record the final temperature after 10 minutes.

Calcualte the temperature difference.

Question 21

Absorption PAG - State the variables and whether they are continuous, discrete or catergoric

Answer 21

Independent - Coulour of the surface (catergoric)

Dependent - Temperature change (continuous)

Controls - Starting temperature (continuous), Surface area (continuous)

Question 22

Absorption PAG - Describe a suitable risk assessment

Answer 22

Boiling water - can burn - place leslie cube in the middle of the desk and stand up

Question 23

Absorption PAG - What graph should you draw why?

Answer 23

A bar chart as one of the variables is categoric

Question 24

Absorption PAG - Describe the expected results

Answer 24

Light shiny surfaces are the best reflectors of heat so will have the highest temperature at the end of the experiment

Dull dark surfaces are the best absorbers and emitters of infrared radiation so they will have the lowest temperature at the end of the experiment.

Question 25

Reflection and refraction PAG - Describe the law of reflection

Answer 25

The angle of incidence = the angle of reflection for a flat plain mirror

Question 26

Reflection and refraction PAG - Describe refraction

Answer 26

The changing of direction of a wave as it enteres a new material.

Question 27

Reflection and refraction PAG - Why does refraction take place?

Answer 27

The new material has a different density so causes a change in speed.

Question 28

Reflection and refraction PAG - When will a wave refract towards the normal?

Answer 28

When the wave slows down

Question 29

Reflection and refraction PAG - When will a wave refract away from the normal?

Answer 29

When the wave speeds up

Question 30

Reflection and refraction PAG - If a wave moves from air into glass how are the following effected?

Speed

Wavelength

Frequency

Answer 30

Speed - slows down

Wavelength - decreases

Frequency - stays the same

Question 31

Reflection and refraction PAG - If a wave moves from glass into air how are the following effected?

Speed

Wavelength

Frequency

Answer 31

Speed - increases

Wavelength - increases

Frequency - stays the same

Question 32

Reflection and refraction PAG - What are the main sources of error and how can they be reduced?

Answer 32

The beam of light spreads out so it is hard to judge the centre of the ray of light.

Use a laser and repeat readings

Question 33

Reflection and refraction PAG - What are the main sources of risk?

Answer 33

The bulb will get hot - this could burn - turn off and let it cool down before moving it

Question 34

Wave measurments (Ripple tank) PAG - Describe how the speed of water waves can be found using a ripple tank

Answer 34

Measure the wavelength using a ruler. Measure across as many waves as possible. Divide the total length by the number of waves.

Measure the frequency using a stop watch. Time for 10 seconds and count how many waves pass a point. Divide the number of waves by 10 seconds to find the frequency.

Calcualte the wave speed using the equation Speed (m/s) = Frequency (Hz) x Wavlength

Question 35

Wave measurments (Ripple tank) PAG - State the wave equation

Answer 35

Speed (m/s) = Frequency (Hz) x Wavlength

Question 36

Wave measurments (Standing waves) PAG - Describe how to calcualte the speed of standing waves.

Answer 36

Record the frequency off the signal generator.

Measure the wavelength with a meter ruler. To make this more accurate measure as many wavelengths as possible and divide the total length by the number of wavelengths.

Calcualte the wave speed using the equation Speed (m/s) = Frequency (Hz) x Wavlength