x.Exhaust.x
Retired Member
1. a) With reference to a p-n junction and in particular the depletion zone, explain how a diode works.
b) Will the diode always only allow current to flow one direction? Why?
2. In a metal, explain why as temperature increases, resistance also increases.
Resistance is how poor a conductor is. It is essentially a measurement of how frequently electrons collide with the lattice structure. As temperature increases, the electrons collide more with the lattice structure, hence metals' resistance increases.
I haven't explained the "why?" part though specifically. Any ideas?
3. Evaluate the signifiance of the Bragg's experiment in understanding the structure of materials.
4. Explain what superconductivity is and WHY ONLY SOME SUBSTANCES ARE ABLE TO BE CLASSIFIED AS SUPERCONDUCTORS.
I don't get the "why" part bolded, but I've explained that superconductivity is a phenomenon whereby a material is able to conduct without any resistance, and excludes all magnetic fields. This will only occur below some critical temperature (Tc).
5. Suggest reasons why BCS theory does not hold for Type II superconductors.
6. Discuss the current limitations of superconductors with more detail placed on cost and temperature.
Temperature (K): 145, 139, 124, 113, 110, 109, 107.
Resistance (Ohms): 1.30, 1.29, 1.16, 1.17, 0.45, 0.01, 0.01.
a) Hypothesise if this new material is a superconductor, if so estimate its critical temperature, if not, estimate the resistance at 0.
Edited: (On a sidenote, this is not my homework. I'm having difficulty with these questions and some of them are syllabus dotpoints. So please don't negatively accuse me
).
Thanks!.
b) Will the diode always only allow current to flow one direction? Why?
2. In a metal, explain why as temperature increases, resistance also increases.
Resistance is how poor a conductor is. It is essentially a measurement of how frequently electrons collide with the lattice structure. As temperature increases, the electrons collide more with the lattice structure, hence metals' resistance increases.
I haven't explained the "why?" part though specifically. Any ideas?
3. Evaluate the signifiance of the Bragg's experiment in understanding the structure of materials.
4. Explain what superconductivity is and WHY ONLY SOME SUBSTANCES ARE ABLE TO BE CLASSIFIED AS SUPERCONDUCTORS.
I don't get the "why" part bolded, but I've explained that superconductivity is a phenomenon whereby a material is able to conduct without any resistance, and excludes all magnetic fields. This will only occur below some critical temperature (Tc).
5. Suggest reasons why BCS theory does not hold for Type II superconductors.
6. Discuss the current limitations of superconductors with more detail placed on cost and temperature.
- Superconductors are costly and are expensive to maintain.
- Its' low temperature makes it impractical and as such, we would need to devise new substances that will be able to superconduct at high temperatures. What else is there?
Temperature (K): 145, 139, 124, 113, 110, 109, 107.
Resistance (Ohms): 1.30, 1.29, 1.16, 1.17, 0.45, 0.01, 0.01.
a) Hypothesise if this new material is a superconductor, if so estimate its critical temperature, if not, estimate the resistance at 0.
Edited: (On a sidenote, this is not my homework. I'm having difficulty with these questions and some of them are syllabus dotpoints. So please don't negatively accuse me
). Thanks!.
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