we used an ice cube mould. One layer was the valence band the other was the conduction band. Marbles were used to represent electrons. It was noted that when an electron migrated from the valence band to the conduction band, it left behind an employ space, that is , a positive hole. Also, when an electron moved from left to right to occupy this hole, the hole "moved" to the left.
Think superconductors and semiconductor are split into two different Dotpoints for a reason.
It is certainly a regurgitating dot point, but I would also add the WW2 short comings in technology. Mobile communciation devices were required for pilots to contact base towers, but thermionic devices were bulky and required significant power to operate and thus more funds were directed towards research into semiconductors. Also, radios were bulky as fk and portable radios were required--> research. Also, with communication technologies getting more and more complex, the overall efficiency of the system was increasing due to the inherent limitations of thermionic devices (heat dissipation, starting time lag, bulky, fragile)--> research towards semi conductors and transistors.
Ye the egg carton one works nice or marbles in a preti dish, you have to talk about movement of holes and electrons as well as how this was simulated in your experiment including a diagram, relating this back to semiconductors to get 5marks.Think superconductors and semiconductor are split into two different Dotpoints for a reason.
If you need an easy one, egg carton will do
I would talk about the inertial and non-inertial frames of reference experiment.
c?A calculation question to get everyone on their game:
I got C. :S Can confirm?A calculation question to get everyone on their game:
how annoying was having to count the number of turns... =.=
Indeed it does. Good job. Can just find "nI" together and substitute into force. (Y)
Since X-rays have extremely short wavelength, Braggs though that by subjecting a crystal structure to X-ray beams information about lattice structure could be gathered. They used an X-ray tube to emit uniform X-ray beams through collimators towards the lattice structure so they remained parallel as they hit the plane. These X-rays were reflected by different lattice planes and some were detected by the detector. These resulted in an interference pattern which the Braggs analysed mathematically (don't think the whole equation is necessary) to find the distance between the planes. This was repeated from different orientation and the same distance was found, suggesting a uniform 3D pattern.
