Oh god i need an a in this to get into ucl arghhhhhhhhhhhhhhhhhhhhhhhh
I'm not going to uni so I'm not really concerned about that. But let me tell you something; revise now, even one hour makes a difference, the hour that you learn something you didn't know, even that hour before the exam. Trust me
So I've gone and revised every topic and done all the old paper as well as the new ones. What do people suggest me do now? Shall I just repeat all the old papers again and make sure im 100% on everything that didn't come up last year
Now that there's a replacement paper I wouldn't bank on the "it came up last year so won't come up again" method guys.
That's true! Although I think it's likely some stuff that came up last year will come up again, there's only so much they can ask after all. Especially in the astrophysics topic
That's true! Although I think it's likely some stuff that came up last year will come up again, there's only so much they can ask after all. Especially in the astrophysics topic
That's true! Although I think it's likely some stuff that came up last year will come up again, there's only so much they can ask after all. Especially in the astrophysics topic
In Astro I suppose yes, although you'll always have classic diagrams, HR graphs and calculations!
The stm microscope is an example of particles (electrons) exhibiting wave like properties. If the gap between the positive plate where the source is placed and the negative tip from where the electrons are released is small enough then electrons can "jump' from the negative tip to the positive plate. The PD across the plates has to be significant enough so that electrons are attracted and they only pass in one direction. If the gap is to wide then transmission will not occur. This is how electrons 'tunnel' across the gap.
That's the concept on how it works.
There are two types of stm microscope.
1 - constant current mode . The fine tip has its height change so that the current on the positive plate is always the same. If the souce gets thicker the tip is moved up and if it gets thinner the tip is moved down. The tip is never more than 1nano metre from the source. The height of the tip is then compared with time and a image can be produced.
2- constant height mode. The tip scans across the source and its gap width varies. This created changing currents on the positive-plate. Current decreases with gap width. Variation of current and time is then used to map out the surface. Again it's never more than 1 nm from the surface.
The stm microscope is an example of particles (electrons) exhibiting wave like properties. If the gap between the positive plate where the source is placed and the negative tip from where the electrons are released is small enough then electrons can "jump' from the negative tip to the positive plate. The PD across the plates has to be significant enough so that electrons are attracted and they only pass in one direction. If the gap is to wide then transmission will not occur. This is how electrons 'tunnel' across the gap.
That's the concept on how it works.
There are two types of stm microscope.
1 - constant current mode . The fine tip has its height change so that the current on the positive plate is always the same. If the souce gets thicker the tip is moved up and if it gets thinner the tip is moved down. The tip is never more than 1nano metre from the source. The height of the tip is then compared with time and a image can be produced.
2- constant height mode. The tip scans across the source and its gap width varies. This created changing currents on the positive-plate. Current decreases with gap width. Variation of current and time is then used to map out the surface. Again it's never more than 1 nm from the surface.
Can someone explain the different sizes of particles effects neutrons.
So in the control rod neutrons need to be absorbed so does that mean the particles inside the rods are similar sizes or smaller?
Same for the moderator, that needs to withdraw ke from the neutrons, does this mean the moderator has similar sized particles so that elastic collisions can take place and the ke be reduced?