VCE Physics Question Thread!

[Bri MT]

No, speed of light is always constant remember that fact if you dont want to bomb the exam

I'm not sure if this is a joke... ?

 - the speed of light is constant (c) under set conditions. All the ray diagram stuff you do with light bending is dependent on light slowing down as it enters a different medium
 - when the electron is being accelerated and approaching c, it is not yet at c (think of c as an asymptote) and its speed is increasing
 - given that I duxed my school for physics I like to think that I didn't bomb the exam  



Edit: this post is not meant as a criticism in any way shape or form

For question 4, wont it be A because the observer has to be in the same frame of reference?

To be in the same frame of reference they need to be travelling at the same velocity, so the observer should be stationary relative to the object

[KiNSKi01]

For question 4, wont it be A because the observer has to be in the same frame of reference?

'location' in A doesn't mean in the same frame of reference (bit misleading)
 B is the answer because if the observer is at rest relative to the object this means they are travelling at the same velocity (therefore they are in the same frame of reference)

[hailstormb]

How is working out shown on Section B of the exam? Do I have to show all lines of working out AND the final answer in the lines provided and then state the final answer in the box, or can I just show working out in the lines, and then the final answer goes in the box without it being stated in the provided lines?

[Bri MT]

How is working out shown on Section B of the exam? Do I have to show all lines of working out AND the final answer in the lines provided and then state the final answer in the box, or can I just show working out in the lines, and then the final answer goes in the box without it being stated in the provided lines?

I always showed both in the lines so that it was easy to see where the answer came from but I don't know if they'd actually penalise you for not doing that

[minhalgill]

does anyone know how to do 2?

is all the voltage in a circuit always used up or lost?

[Bri MT]

does anyone know how to do 2?

is all the voltage in a circuit always used up or lost?

2. You need to consider whether length will be contracted or dilated & whether or not this occurs only in the direction of motion

Voltage is a measure of difference in potential, which may help you conceptualise this.  (The answer is yes)

[KiNSKi01]

Yo what evidence do we need to know which supports the wave model of light?

As in which experiments and their observations which support the wave model

[sweetiepi]

Yo what evidence do we need to know which supports the wave model of light?

As in which experiments and their observations which support the wave model

Experiment: Young's Double Slit experiment

A couple of notable observations:
Diffraction- in Young's Double Slit, obstacles are placed in the path of a wave will not directly block the wave, rather the wave can bend around the barrier. Particles don't do this.

Superposition- Peaks add together in two ways:
- Constructive interference (two crests + two troughs that add up to make a big peak- an antinode)
- Destructive interference (a crest and a trough cancel out- node)

(This took me an embarrassing while to remember from what I've actually relearnt for one of my units this semester- I'm not 100% certain on how much of this is still in the SD )

[KiNSKi01]

Ok thankyouuu

Correct me if I'm wrong but other than photoelectric effect, single-slit experiment can also support the particle model of light?

Just trying to make sure I don't get confused between double-slit and single-slit when discussing wave/particle models of light

[sweetiepi]

Ok thankyouuu

Correct me if I'm wrong but other than photoelectric effect, single-slit experiment can also support the particle model of light?

Just trying to make sure I don't get confused between double-slit and single-slit when discussing wave/particle models of light

I don't know about the single-slit experiment (and I was finding conflicting info online), however for the particle nature of light, I'd hands-down say photoelectric effect is the main experiment/evidence

[Freddie Hg]

Ok thankyouuu

Correct me if I'm wrong but other than photoelectric effect, single-slit experiment can also support the particle model of light?

Just trying to make sure I don't get confused between double-slit and single-slit when discussing wave/particle models of light

The single slit proves the dual nature of light as both waves and matter

does anyone know how to do 2?

is all the voltage in a circuit always used up or lost?

for 2 you have to consider in what situation of the lorentz factor will have no change on mass length and time, just take a look at the equations

mod edit (insanipi): merged posts

[Bri MT]

The single slit proves the dual nature of light as both waves and matter

Absolutely - but I'm always cautious about words like "proves" in science subjects

In regards to these experiments make sure you know why They support a particular model & what we would expect, for example,  from the double slit experiment if light didn't have wave properties

[Freddie Hg]

Absolutely - but I'm always cautious about words like "proves" in science subjects

In regards to these experiments make sure you know why They support a particular model & what we would expect, for example,  from the double slit experiment if light didn't have wave properties

Yeah i have to agree with you. rookie mistake, for minhaigill's questions what are the answers?  i got b and c respectively for 1 and 2

[KiNSKi01]

The single slit proves the dual nature of light as both waves and matter

Ok sickkkk

[AnonymooseUser]

I'm still a little bit confused on significant figures for the exam (I looked at the other thread on the front page), so was wondering if anyone could help.

Say for example I had a final value for a problem of 10.16. How do I figure out the number of significant figures required? That is, how do I know whether my answer should be 10, 10.2 or 10.16 etc?

Also, can you be penalised in the exam for incorrect significant figures?

Thanks!