Required Practicals

37 flashcards · Physics · by Ella Corcoran

1. g by free fall measurements and instruments

   Time t for slider to fall between two points, using light gate and data logger distance d between two light gates - ruler

2. g by free fall purpose

   find the value of g by allowing a slider to fall under gravity light gates used to find time for slider to fall between two points

3. g by free fall what changes and range

   distance between light gates- top is fixed, bottom moves between 20 cm-60 cm

4. g by free fall constant

   -distance slider had to fall before passing though light gate - slider is always dropped from very top - therefore speed that slider is travelling as it passes first gate is constant

5. g by free fall use of results

   - rearrange s=ut+ ½at² to get 2s/t=at+2u, which is in the form y = mx+c - 2s/t on y axis - t on x axis

6. Young Modulus of a wire purpose

   find Young Modulus (Y or E) of a wire load then unload a wire and find how average extension of wire changes

7. Young Modulus of a wire what are the measurements made and the instruments used?

   Diameter, d, of wire - micrometer Initial length, l, of wire - ruler change in length ∆l, of wire - Vernier scale mass, m, on wire - balance

8. Young Modulus of a wire changes and ranges

   mass on wire up to 2 kg wire loaded then unloaded so average value for change in length can be calculated

9. Young Modulus of a wire Constant

   the wire - control wire is used to compensate for any changes in length due to wire getting hotter or colder so expanding or contracting

10. Young Modulus of a wire use of results

    force on wire from F=mg and cross-sectional area of the wire from A=πd²/4 the stress can be found from F/A strain is found from ∆L/L

11. Resistivity of a Wire purpose

    to find resisitivity of a metal wire Vary the length of a wire and find how the resistance changes

12. Resistivity of a wire measurements + instruments

    length, l, of wire - ruler current, I , ammeter Potential difference, V, across length of wire - Voltmeter Diameter,d, of wire - micrometer

13. Resistivity of a wire changes and ranges

    - length of wire across which potential difference in being measured - 0 cm-100 cm

14. Resitivity of a wire constant

    - current through wire maintained at low value to minimise heating effects

15. Resistivity of a wire use of results

    - resistance of length of wire, R, calculated from R=V/I - cross sectional area, A, of the wire is calculated from A=πd²/4 - putting equation R = ρL/A into y = mx + c gives R = ρ/A x L (with R on y axis and L on x axis)

16. Emf and internal resistance purpose

    find emf and internal resistance of cell (or battery) vary current flowing though cell by changing load resistance in circuit and find pd across load resistance

17. Emf and internal resistance measurements and instruments

    - current, I, ammeter - Potential difference, Vload, across resistor - Voltmeter

18. Emf and internal resistance change + ranges

    - resistance of resistor 0 - 14 Ω NB- resistance of resistor does not need to be recorded- just needs to vary to high value compared to internal resistance of cell

19. Emf and internal resistance Constant

    - emf of cell - switch off circuit between measurements - so cell isn't discharged

20. Emf and internal resistance use of results

    rearrange E = Vload + Ir into y = mx + c to get Vload =-rI + E Vload on y axis I on x axis

21. Stationary waves on a string (relationship to Length) purpose

    -confirm relationship between frequency of first harmonic on a string and length of the string -Vary the length of string, and adjust frequency of the signal generator until first harmonic is visible

22. Stationary waves on a string (relationship to Length) measurements + instruments

    - frequency, f, at which the first harmonic appears - signal generator - length, l, of the string that is oscillating (at first harmonic) - ruler - mass, m, on the end of the - total length, L, of the whole string - ruler - total mass of the whole string, M, - balance

23. Stationary waves on a string (relationship to Length) changes+ranges

    -length of the string between the oscillator and the triangular bridge - 20 cm - 80 cm

24. Stationary waves on a string (relationship to Length) constant

    -mass on string - tension constant - same string is used - mass per unit length constant

25. Stationary waves on a string (relationship to Length) use of results

    -Tension, T, of string is found fromweight of the masses on the end of the string, T = mg -mass per unit length, µ, is given by µ= M/L -rearrange f= ½l √(T/μ) into y = mx, getting f = ½ √(T/μ )x 1/l -f on the y-axis - 1/l on the x-axis

26. Stationary waves on a string (relationship to Tension) purpose

    confirm relationship between frequency of first harmonic and tension Vary mass on end of string, adjust frequency of signal generator until first harmonic visible

27. Stationary waves on a string (relationship to Tension) Measurements + instruments

    -frequency, f, at which first harmonic appears - signal generator - length, l, of string that is oscillating (at first harmonic) - ruler - mass, m, on end of string - balance -total length, L, of whole string - ruler -total mass of whole string, M, - balance

28. Stationary waves on a string (relationship to Tension) changes+ranges

    -mass on end of string- hence Tension of string - 200 g to 1,000 g

29. Stationary waves on a string (relationship to Tension) constant

    -length of string between oscillator and triangular bridge -same string is used throughout- mass per unit length remains constant

30. Stationary waves on a string (relationship to Tension) use of results

    -Tension, T, of string is found from weight of masses on end of string, T = mg - mass per unit length,µ, is given by µ= M/L

31. Young's slits purpose

    -find the wavelength of laser - Vary distance between screen and double slits and find how fringe separation changes

32. Young's slits changes+ ranges

    -distance between screen and double slits - 0.5 m to 3.0 m.

33. Young's slits Measurements+ instruments

    -fringe spacing of 10 adjacent fringes, w₁₀ - ruler - distance, D, between screen and double slits - ruler -Slit separation, s, - travelling microscope

34. Young's slits constant

    -slit separation, s, between double slits -laser -wavelength of the laser

35. Young's slits safety

    -Do not look along the beam of the laser -Use a non-reflective screen -Put a warning sign on the door

36. Young's slits use of results

    - width of a single fringe, w, is found by dividing w₁₀ by 10. - rearrange w = λD/s into y = mx, giving w = (λ/s) x D w on the y-axis D on the x-axis.

37. Diffraction purpose

    -find wavelength of laser. -Measure angle of different maxima produced as laser passes through diffraction grating and find average wavelength for the laser.