| What has to be the case for a wave to diffract through a slit? | The wavelength has to be smaller or similar sized to the slit |
| How would one comment on the relationship between the first fringes width and the latar fringe widths when descusing single slit diffraction | The first fringe is considerably greater than that of the rest |
| What type of waves does diffraction occur upon | Both transvers and longitudinal |
| What frequency of wave is the best at defracting around objects? | High |
| What are the condistions for an interference experiment of two waves that makes them more easily observable? | - Separation between the two coherent sources needs to be as small as possible
- Distance between the two coherent sources and the screen need to be as large as possible |
| What can be said about the displacement of two waves for constructive interference to occur? | displacement in the same direction |
| What can you say regarding the displacement of two waves for destrcutive interference to occur? | one wave has positive displacement and the other has negative displacement |
| What can be said about the displacement of two waves for total destructive interference to occur? | equal but opposite displacements |
| Why are lasers a good light source for interference patterns | They give clear patterns |
| What is the fringe spacing formula | fringe spacing = (lamda X distance between the double slits and the screen) / slit seperation |
| Why does the slit size have to be >= the waves wavelength? | The fringe seperation woud be too large to observe |
| What is interference | The result between two waves interacting together |
| What are the absolute necassary condistions for interference of two waves? | - Same frequency
- Constant phase differnce
- Same amplitide
- Same medium
- The two interference waves need to be propagated along the same direction so that their vibrations are along a common line |
| What 3 things define a wave as being coherent | constant phase
same wavelength
same frequency |
| Define path difference | Difference in distances travelled by two waves to a given point |
| Whats the equation for destructive interferene of two waves? | (n + 0.5) number of wavelengths, where n is an integer |
| Whats the equation for constructive interferene of two waves? | n number of wavelengths, where n is an integer |
| What are the differences of white light and monochromatic light for single slit diffraction | The central maximum would be white
All maxima would be composed of a spectrum
The shortest wavelength (violet / blue) would appear nearest to the central maximum
The longest wavelength (red) would appear furthest from the central maximum
The fringe spacing would be smaller and the maxima would be wider |
| Whats the effect of increasing the wavelength for a single slit experiment | Light diffract more, therefore wider fringes |
| Whats the effect of increasing the slit width for a single slit experiment | Intensity increase
Fringe spacing wider |
| Whats the effect of increasing the slit spacing for a double slit experiment | Fringes are more tightly compact
More divisions within the central maxima |
| Whats the effect of increasing the distance between the screen and the slits for a double slit experiment | Fringes more widely spaced |
| Whats the effect of increasing the wavelength for a double slit experiment | Fringes more widely spaced |
| Whats the effect of increasing the slit width for a double slit experiment | Interference pattern will become wider and wider till they will start overlapping each other, making the fringes less distigishable
The screen will become brighter |
| Whats the effect of decreasing the distance between the screen and the slit for a single slit experiment | Interference pattern will become wider and wider till they will start overlapping each other, making the fringes less distigishable (fringe spacing (w) will become smaller)
The screen will become brighter |
| Whats the effect of increasing the slit spacing for a single slit experiment | S |
| How would you describe the width of the maximas for the interference pattern for double slit | All the same |
| What changes could be made to any interference pattern in order to make it more accurate | Increase the distance between the screen and the slit
Measure across many maxima |
