Physics Pop Quiz

microbiek

JC 2K3 wrote:

A whole chapter.... how did you miss that?

rely? can u give me a kind of contents of what it involves?? em what book do you have

carlowboy

Fobia wrote:

Actually, sorry for being off-topic, but I have a similar question. On the monochromatic light exps, does one need to know both or are you guaranteed to be able to do either (Ie, spectrometer or laser method)?

Either method will do but you're expected to know the layout of the spectromoter for section B

Turnip2000

Was I the only who missed the whole mono-chromatic light bit because I was laughin soooo much at "young slits" ...got me every time!!!

Technicly you dont need to know electricity if you know everything else!!

Feddd

microbiek wrote:

rely? can u give me a kind of contents of what it involves?? em what book do you have

Coloumbs law, Charging bodys by induction, electric feilds and the like. You prolly did it but your teacher may have included it in another chapter or something.


Q: When a proton meets an antiproton and they annihilate eachother, why are additional particles produced with the photons and not just the photons?

carlowboy

Do you mean with the photons or that when photons convert energy to mass?

If you mean with the photon, surely they will be there for conservation of momentum?

Feddd

Turnip2000 wrote:

Technicly you dont need to know electricity if you know everything else!!

I plan on not answering any electricity. Shorts/mechanics/option/Q12/Nucleus/electron is my A team. ofc, might have to do some elec in expts or the shorts/Q12.

genericgoon

yes electricity is quite hard.

Cipriana

What's the proof for n(lambda)=dsin0?
Do you have to draw the diagram, or can you prove it in mathematical terms?

Turnip2000

Cipriana wrote:

What's the proof for n(lambda)=dsin0?
Do you have to draw the diagram, or can you prove it in mathematical terms?

The answer to that question is dont bother your hole with light!!

JC 2K3

It's just a triangle with hypotenuse d and opposite site n(lambda).

You have to draw the diagram to show where you've derived that triangle from though.

chas_88

Turnip2000 wrote:

Was I the only who missed the whole mono-chromatic light bit because I was laughin soooo much at "young slits" ...got me every time!!!

oh yes, the young sluts experiment, as we called it!

Nehpets

If a diffraction grating had 300 lines per mm in an exp... Explain how using a diffraction grating of 500 lines per mm leads to a more accruate result?

(smaller % error and images further apart? but how/why?)

chas_88

Nehpets wrote:

If a diffraction grating had 300 lines per mm in an exp... Explain how using a diffraction grating of 500 lines per mm leads to a more accruate result?

(smaller % error and images further apart? but how/why?)

greater diffraction occurs because the distance between the lines is closer to the wavelength of light, in a grating of 500 lines per mm than one with 300 lines per mm.

define U-value.

Splicer

heya

anyone know the difference between a POTENTIOMETER and POTENTIAL DIVIDER?

E92

carlowboy wrote:

Séard is dlí doppler ann ná an athrú sa minicíocht dealraithe agus é ag gluaiseacht i dtreo nó ón féachadóir.

An ráiteas thuas as Béarla, máis é do thoil é?

E92

Fobia wrote:

Red shift is hardly a "use"..

Whats the red shift? I feel like I'm asking an incredibly stupid question, but nevertheless I'd like to know the answer.

Nehpets

E92 wrote:

Whats the red shift? I feel like I'm asking an incredibly stupid question, but nevertheless I'd like to know the answer.

Doppler effect is used by astronomers. They look at the light emitted by different stars and measure the frequency of the different wavelengths and therefore the colours. They then compare them to similar colours on earth and they found the freq. of the waves from the stars is always decreasing meaning the stars are moving away from us (supports the big bang theory i.e the universe is always expanding and spreading as if it came from a single point)

It's known as the "red shift" because red light has a low frequency.

EDIT: So yeah, the "red shift" would be a "use" for the doppler effect. It's accepted I think 2003 Q.7 asks for applications and it would be one of the answers

E92

Splicer wrote:

heya

anyone know the difference between a POTENTIOMETER and POTENTIAL DIVIDER?

AFAIK they both are the same instrument, but you connect them to the circuit differently.
I think a potential divider is whats used to vary the Current, whereas the Potentiual Divider is for varying Current. However that doesnt make a lot of sense to me, because if you vary Pd then you do end up varying current. Methinks there is something to do with resistance in there as well.

Noit 100%, so I'd love a bit of help on it.

Nehpets

chas_88 wrote:

greater diffraction occurs because the distance between the lines is closer to the wavelength of light, in a grating of 500 lines per mm than one with 300 lines per mm.

define U-value.

The U-Value of a structure is the amount of heat energy conducted per second through 1m^2 of that structure when a temperature difference of 1K is mainted between it's ends.

Define (i) Specific Heat Capacity, (ii) Specific Latent Heat (12 marks!)

ApeXaviour

A potentiometer is one resistor with variable junctions. i.e. you can vary your output voltage by changing where the leads exit it. It acts in much the same way a potential divider does. Except in the latter case there are two resistors with a fixed junction between them instead of on them.

Carry on

carlowboy

E92 wrote:

carlowboy wrote:

Séard is dlí doppler ann ná an athrú sa minicíocht dealraithe agus é ag gluaiseacht i dtreo nó ón féachadóir.

An ráiteas thuas as Béarla, máis é do thoil é?

The doppler effect is the change in frequency of a body as it trabels towards or away from the observer.

Limerick Dude

carlowboy wrote:

E92 wrote:

carlowboy wrote:

Séard is dlí doppler ann ná an athrú sa minicíocht dealraithe agus é ag gluaiseacht i dtreo nó ón féachadóir.


The doppler effect is the change in frequency of a body as it trabels towards or away from the observer.

Make sure you say APPARENT change in frequency.


What is the thermometric property in a thermocuple?

carlowboy

yeah, I prefer writing it in irish. apparent= dealraithe.

Limerick Dude

Nehpets wrote:

The U-Value of a structure is the amount of heat energy conducted per second through 1m^2 of that structure when a temperature difference of 1K is mainted between it's ends.

Define (i) Specific Heat Capacity, (ii) Specific Latent Heat (12 marks!)

Specific Heat capacity is the amount of heat energy required to change the temperture of 1kg of a substance by 1K. Measured in J KG K

Specific latent heat is the amount of heat energy required to change the state of 1kg of a substance without a change in temperature. Measured in J KG

Jonathan

Limerick Dude wrote:

What is the thermometric property in a thermocuple?

Voltage.

Give the nuclear equations for both pair production and pair annihilation

carlowboy

e^-1 +e^+1 -> 2 gamma

gamma -> e^-1 + e^1

Who put forward the idea of the neutrino and why?

Jonathan

carlowboy wrote:

Who put forward the idea of the neutrino and why?

Pauli. Because the principal of conservation of energy was not holding true. He blamed the discrepancies on Neutrinos.

Jonathan

Give an equation that defines temperature on the Celsius scale

carlowboy

C= K- 273.15

Tell me newton's second law and derive the subsequent equation from it. (a lot of marks there)

Jonathan

carlowboy wrote:

C= K- 273.15

I wrote that in my mock and got nothing. its

t=T-273.15