Required Practicals Flashcards
(RP.1) Draw the Set up for the investigation of the variation of frequency of stationary waves on a string with length tension and mass per unit length
(RP.1) State any safety Precautions for the investigation of the variation of frequency of stationary waves on a string with length tension and mass per unit length
. Place a suitable Crash bad under the weights to prevent floor damage if the rope fractures
. Don’t Place feet under the weights
. Wear Goggles for protection if the wires break
(RP.1) for the investigation of the variation of frequency of stationary waves on a string with length tension and mass per unit length
Briefly Explain how you’ll investigate the relationship between frequency and mass per unit length
The Fundamental frequency should be found for Different Wires (different mass per unit length)
Keeping Length and Tension identical
Plot a graph of f^2 against 1/(mass per unit length) as per the formula
Straight line through origin proves inverse proportion to f^2 and mass per unit length
(RP.2) Draw the Set up for the investigation of the interference effects to include the Young’s slit experiment and interference by a diffraction grating
(RP.1) Explain the essential theory of the variation of frequency of stationary waves on a string with length tension and mass per unit length
If the wire is plucked
It will vibrate at its fundamental frequency with nodes at each end
Distance between nodes is 1/2 of a wavelength, so the wavelength is double this distance
f = 1/2L * (Tension/Mass per unit length)^1/2
for consecutive Harmonics multiply the harmonic number by the frequency
(RP.2) Explain the essential theory for the investigation of interference effects to include the young’s slit experiment and interference by a diffraction grating.
When Monochromatic Light such as a laser beam, is shone through a diffraction grating.
An interference pattern is shown
There is a central bright maximum with further maximum of decreasing intensity either side.
the angle of a particular maximum to the normal, is given by the equation
(RP.2) Explain how to conduct the experiment for the investigation of interference effects to include the young’s slit experiment and interference by a diffraction grating
Adjust the distance D between the grating and the screen until a number of orders can be seen and sufficiently apart to be measured with a millimetre scale
Secure a piece of paper to the front of the screen
Mark the centre of the maximas then switch the laser off
Remove the piece of paper and measure the distance between the maxima between each of the 1st orders
then determine the angle between by using tanx=(distance between maximas*0.5 / Distance to screen)
(RP.2) Explain the safety precautions for the investigation of interference effects to include the young’s slit experiment and interference by a diffraction grating
. Never look directly into beam
. Never point the beam at a person
.Avoid reflections of the beam
. Always point you back to the lasers when it is on
.Switch laser off when not in use
(RP.2) Explain how the uncertainty can be reduced for the investigation of interference effects to include the young’s slit experiment and interference by a diffraction grating
Move the screen further away to increase the distance between maximas
Use a grating with smaller line separation to increase distance between maximas
(RP.2) Explain the essential theory for the investigation of interference effects to include the young’s slit experiment and interference by young’s double slit
Wavelength can be determined by using a double slit to produce an interference pattern
By measuring the slit spacing, fringe spacing and distance to the screen
The formula can be used to calculate the wavelength of light
(RP.2) for the investigation of interference effects to include the young’s slit experiment and interference
How could a student determine the fringe separation more accurately
Measure across several fringes
Work out the mean fringe spacing between maxima
mark maxima within dark fringes instead of bright fringes
(RP.3) Explain the essential theory of the determination of g via free fall method
free falling = object falling vertically under gravity with no other forces acting on it
Falling within air will produce air resistance, but provided the object is made of dense material and its speed isn’t excessive we can consider it negligible
with this assumption we then use the equations for uniformly accelerating (SUVAT)
s= ut + 1/2at
if the object is released from rest u=0 and the object falls height h
h = -1/2gt^2 where g = -9.8
therefore t^2 = 2/g * h
Plot a graph of t^2 y-axis and h x-axis
gradient = 2/g
(RP.3) Explain how to conduct an experiment for the determination of g via free fall
Time is measured using an electronic stop clock that reads to a 1/100 th of a second
When the switch is open the electromagnet should hold the steel ball bearing in place
When the switch closes the ball is released and the stop-clock simultaneously activates
The clock stops when the ball its the trapdoor
Repeat the experiment at least 3 times and average the time for this height
Repeat over multiple heights
(RP.3) Explain the safety precautions for the determination of g via free fall
Make sure no short circuits occur but including resistors
A suitable container should be placed under the trapdoor to catch the ball bearing
and prevent a trip hazard forming
(RP.2) Draw the set up for the investigation of interference effects to include young’s slit experiment and interference by diffraction grating
Explain the essential theory for determining the modulus of a material by a simple method
Young’s modulus = Stress/Strain
Rearranging we can get F = EA/L * Delta L
A Graph of applied force F against extension will produce a linear graph of gradient EA/L which we can use to derive young’s modulus
(RP.4) Explain how to conduct an investigation for determining the young’s modulus of a material by a simple method
Draw a diagram for this
Thin copper wires should be tightly clamped to avoid slipping and should be as long as possible
Weights are added until the wire is taut and the initial reading of the marker is taken
Extension is then determined for additional loads
(RP.4) What are the safety precautions that should be observed filer the investigation of a materials young modulus
Place a suitable Crashpad under the weight to prevent damage to floor if the wire fractures
Don’t place feet under weights
Wear goggles for protection if the wire breaks
(RP.5) Explain the Essential theory of the determination of the resistivity of a wire
(p = Roe = resistivity)
Resistivity is given by the equation R = pL/A (R = Resistance, L = Length of wire, A = Cross sectional Area)
Plot R on the y axis against L
Linear line through the origin with gradient p/A
If we Determine A then we can determine p
(RP.5) Explain how to carry out an investigation of the determination of a wires resistivity
Draw a diagram for this
Connect a cell, ammeter in series with a voltmeter in parallel to a length of wire with crocodile clips either end that can be moved
For varying lengths of wire create a set of data for voltages & Current and use V/I = R to calculate resistances
(RP.5) Explain the safety precaution for the investigation of a wires resistivity
Explain the other benefit to this precaution
Connect a resistor within the circuit to prevent short circuiting
A current larger then 0.5Amps could heat the wire and therefore change its resistivity due to increase in temperature
(RP.6) Explain the essential theory for the investigation of the emf and internal resistance of cells
When there’s a current within an electrical cell
Terminal PD < EMF of the cell
Because work has to be done overcoming the internal resistance
Can be expressed with V = emf - I*(internal res)
If we measure the PD for different values of the current via a variable resistor
Plot a graph of V against I, a linear graph will form of a gradient of -(Internal res) and a y-intercept of the emf
(RP.6) Explain the safety precautions for the investigation of emf and internal resistance of a cell
Connect a resistor within the circuit to prevent short circuiting when the variable resistor is on minimum value
