Physics Required practicals Flashcards
INVESTIGATING SPRINGS
What is the equation linking Force, extension and spring constant?
INVESTIGATING SPRINGS
F = ke
Force = Spring constant x Extension
INVESTIGATING SPRINGS
What is the equation for elastic potential energy?
INVESTIGATING SPRINGS
E = 1/2(ke^2)
Elastic potential energy = 1/2 x spring constant x estension^2.
INVESTIGATING SPRINGS
What is a source of error in this practical?
INVESTIGATING SPRINGS
Not measuring extension accurately.
ACCELERATION
What are the 2 equations for acceleration?
ACCELERATION
1) a = F/m (F = ma) - tested in this practical
2) a = (V-U)/t = (Change in velocity / time)
ACCELERATION
What are the 3 variables?
ACCELERATION
I = Force
D = Acceleration
C = Mass over whole apparatus stays same, trolley
ACCELERATION
What is the method for this practical?
ACCELERATION
1) Set up trolley with piece of card with gap to interrupt light gate. Software calculates acceleration.
2) Add masses to hook on string, provides accelerating force (mass of hook x acceleration due to gravity)
3) Repeat this twice with readings
ACCELERATION
What are some sources of error?
ACCELERATION
- Mass off string not put into trolley
- Friction between trolley, use air instead
- String loose when released
WAVES: RIPPLE TANK
What is the method for this practical?
WAVES: RIPPLE
1) Set up a ripple tank so that it has a set frequency
2) Measure the distance between 10 wave crests and then divide it by ten to get 1 (average) wavelength
3) Do the same for frequency, calculate wave speed
WAVES: RIPPLE TANK
What is a source of error? How can you solve this?
WAVES: RIPPLE TANK
Hard to measure the wavelength/frequency. To solve this take a photo of the ripple tank.
WAVES: STRINGS
How can you measure wavelength from a vibrating string?
WAVES: STRINGS
With a metre stick, measuring the distance between nodes (or full cycle)
WAVES: STRINGS
How could you make sure that the measurement of wavelength is accurate?
WAVES: STRINGS
Use a strobe light to the same frequency to light the oscillations.
WAVES: BOTH
What is the equation common in both waves practicals?
WAVES: BOTH Wave speed (m/s) = Frequency (Hz) x Wavelength (m)
LIGHT
In what conditions should light experiments be done in?
LIGHT
Dark conditions
LIGHT
Where do you measure angles from?
LIGHT
Always from the normal for angles of incidence, reflection and refraction.
LIGHT
What is the independent (changing) variable?
LIGHT
Material used or angle of incidence
LIGHT
What is the dependent variable?
LIGHT
Angles of reflection and refraction
LIGHT
How do you know that you have conducted the experiment accurately?
LIGHT
The angle of incidence should ALWAYS equal the angle of reflection.
LIGHT
How does the density of a material affect the behaviour of light?
LIGHT
Usually the denser the material, the slower light travels through it, bending towards the normal.
LIGHT
What are some sources of error?
LIGHT
- Moving the block
- Light from ray box spreading out
RADIATION + ABSORPTION
What is the method for this practical?
RADIATION + ABSORPTION
1) Put Leslie cube on a heat proof mat
2) Fill with water and leave to warm up
3) Use thermometer to measure temp of each side, all same temp
4) Use an IR detector to record he amount of IR radiation for each side, distance from cube same
5) Find out black sides emit more IR radiation
RADIATION + ABSORPTION
What are black bodies?
RADIATION + ABSORPTION
Perfect absorbers and emitters of all radiation.
RADIATION + ABSORPTION
What needs to be controlled?
RADIATION + ABSORPTION
The water temperature inside the cube - same for each reading.
RADIATION + ABSORPTION
Why should you take repeat readings?
RADIATION + ABSORPTION
To make sure that the results are repeatable.
