HSC Physics Question Thread

[The Slow Hare]

What’s the difference between a solar cell and a photocell. From my understanding solar cell uses light hits the semiconductor complex which induces a current in the external circuit. But isn’t the photocell the exact same.
*Askin this question because I have to draw two sperate diagrams for them but I don’t know what the difference is.

P.S. first time posting a question, so if I did anything wrong -> pls don’t hate

[S200]

What’s the difference between a solar cell and a photocell. From my understanding solar cell uses light hits the semiconductor complex which induces a current in the external circuit. But isn’t the photocell the exact same.
*Askin this question because I have to draw two sperate diagrams for them but I don’t know what the difference is.

P.S. first time posting a question, so if I did anything wrong -> pls don’t hate

Although I couldn't help you with the diagram, a quick google search gives this...

A solar cell produces power for an electrical circuit while a photocell is a light-activated control switch. ... The only commonality between the two is that light is needed for them to work. Solar cells can be found everywhere, while photocells are hidden.

[envisagator]

What’s the difference between a solar cell and a photocell. From my understanding solar cell uses light hits the semiconductor complex which induces a current in the external circuit. But isn’t the photocell the exact same.
*Askin this question because I have to draw two sperate diagrams for them but I don’t know what the difference is.

A solar cell is a device that converts sunlight into electrical energy using a p-n junction. Basic working principle is: When light (photons) of a sufficiently high frequency hits the cell, each photon of light frees an electron from the junction between the layers, thus creating holes and free electrons. The free electrons flow to the n-type layer and the holes to the p-type layer. This creates an electric potential between the layers. The electrons flow via the external circuit to the p-type layer, releasing energy to the load.

A photocell on the other hand is a device that converts light energy into electrical energy by the photoelectric effect. Basic principle: A light source is directed towards a semi-conductive metal plate, causing electrons to be emmited by the photoelectric effect; the metal plate is curve so that the photoelectrons emitted are focused towards a collecting anode and subsequently pass through an external circuit as current. Used in motion detectors.

Hope this helps

[key to success]

Although I couldn't help you with the diagram, a quick google search gives this...

Although I couldn't help you with the diagram, a quick google search gives this...

The answers here are pretty thorough but very simply put;
solar cells- need light hence photocurrent to make devices work (power produced is used)
photocells- need an absence of light- photocurrent to trigger a switch to make things work

[Dragomistress]

Hey,
I am wonder why this is the case. A piece of silicon is doped with an element from group V of the periodic table and it has no overall charge? Why does it have no overall charge?

[Dragomistress]

Also, I am wondering why this is the case.
In an experiment to demonstrate the photoelectric effect, it was found that when light with a frequency f and an intensity I was shone on the cathode, the voltage needed to completely stop the photoelectric current was V volts. The effect of increasing the incident light intensity shining on the cathode is that the voltage V needed to be:

Answer: kept the same.

[envisagator]

Hey,
I am wonder why this is the case. A piece of silicon is doped with an element from group V of the periodic table and it has no overall charge? Why does it have no overall charge?

In the most basic way I could explain this is the fact that the impurity atoms (the dopant) is already in a neutral state, so when it is added to a neutral solid (semiconductor) the overall charge remains zero.

Hope this helps

[jamonwindeyer]

Also, I am wondering why this is the case.
In an experiment to demonstrate the photoelectric effect, it was found that when light with a frequency f and an intensity I was shone on the cathode, the voltage needed to completely stop the photoelectric current was V volts. The effect of increasing the incident light intensity shining on the cathode is that the voltage V needed to be:

Answer: kept the same.

Increasing the intensity of the light means that you have more photons striking the metal. This means more released photoelectrons, so, more current! However, each individual electron still has the same energy, since this is determined by frequency, not intensity. Energy per electron is what voltage depends on, so the voltage is the same even though the current is larger

[Duarashid]

Hi! Im not sure what to label my Y axis for the black body emission spectrum graph (incase we have to draw it). I've seen a few images, with 'Spectral energy density' and others with 'intensity'. I know for the X-axis it is wavelength. Should I write the units too?

Thanks

[jamonwindeyer]

Hi! Im not sure what to label my Y axis for the black body emission spectrum graph (incase we have to draw it). I've seen a few images, with 'Spectral energy density' and others with 'intensity'. I know for the X-axis it is wavelength. Should I write the units too?

Thanks

Hey! Intensity is totally fine on the Y-Axis. If you wanted units, you could put W/m^2, but I doubt they'll stress that much in a diagram of the graph spectral radiance is similar to intensity, but it has a more specific and more complex definition, so just roll with intensity

[moq418]

How to draw a transformer diagram

[mxrylyn]

Do all students in a school have to do the same option?

We have started the term with only 4 weeks to fully learn the option module before trials.

At the beginning of the year we were told that we would be doing from Quanta to quarks. So anticipating this 4 week crunch , I spent a lot of time last term pre learning and writting out Sylabus dot points for Quanta to quarks.

However we have a new teacher this term and they have decided that we will be changing to astrophysics. I really want to still do quantum quarks as I already know it extremely well and spent numerous hours on it last term and I was wondering if it is possible for me to do Quanta to quarks in the HSC while everyone else in the class does astrophysics.

I'm still happy to do the class assessments as they are on astrophysics.

Note: there is only two of us in the class

[S200]

-snip-

Do all students in a school have to do the same option?

We have started the term with only 4 weeks to fully learn the option module before trials.

At the beginning of the year we were told that we would be doing from Quanta to quarks. So anticipating this 4 week crunch , I spent a lot of time last term pre learning and writting out Sylabus dot points for Quanta to quarks.

However we have a new teacher this term and they have decided that we will be changing to astrophysics. I really want to still do quantum quarks as I already know it extremely well and spent numerous hours on it last term and I was wondering if it is possible for me to do Quanta to quarks in the HSC while everyone else in the class does astrophysics.

I'm still happy to do the class assessments as they are on astrophysics.

Note: there is only two of us in the class

Ditto the numbers,

If HSC is anything like VCE, and you are referring to individual module analysis, I would say no.
Bear in mind that I am not a HSC specialist.

[jamonwindeyer]

How to draw a transformer diagram

Hey! The key elements would be the two coils wrapped around a core, all labelled (including designating which is the primary core). Optionally you could show things like where the magnetic flux and current are flowing! Pretty much any diagram you've seen in a textbook or similar will do the trick

Do all students in a school have to do the same option?

We have started the term with only 4 weeks to fully learn the option module before trials.

At the beginning of the year we were told that we would be doing from Quanta to quarks. So anticipating this 4 week crunch , I spent a lot of time last term pre learning and writting out Sylabus dot points for Quanta to quarks.

However we have a new teacher this term and they have decided that we will be changing to astrophysics. I really want to still do quantum quarks as I already know it extremely well and spent numerous hours on it last term and I was wondering if it is possible for me to do Quanta to quarks in the HSC while everyone else in the class does astrophysics.

I'm still happy to do the class assessments as they are on astrophysics.

Note: there is only two of us in the class

Hey! Definitely can do whatever option you like in the external exam - If you prefer Q2Q, get through your internal assessments on Astro then swap over for the HSC exam! Make sure you can handle learning it properly without any direct help from your teacher

[Dragomistress]

Why are superconductors used on a maglev train?