Question

Although you can see the pencil, it appears broken in the glass of water. This is because
A)
electromagnetic waves cannot travel through solids.
B)
electromagnetic waves travel at different speeds through different media.
C)
electromagnetic waves compress more when they travel through denser media.
Eliminate
D)
electromagnetic waves get closer together when they go through dense media like glass.

Answer 1

light from rarer medium to denser medium moves towards the normal

Answer 2

so b?

Answer 3

@Michele_Laino what do you think?

Answer 4

your drawing is correct!

Answer 5

so the answer would be ?

Answer 6

I think that option B is \(not\) a wrong option

Answer 7

but is there another one that could be correct? just asking because if so i need to report this question to my teacher

Answer 8

according to the drawing of @rvc , I think that also option D is correct!

Answer 9

C i suppose

Answer 10

from denser to rarer ---> away from normal

Answer 11

sorry, electromagnetic waves don't compress any medium I think @rvc

Answer 12

oh i read the satement wrong oops

Answer 13

yep D

Answer 14

so only b?

Answer 15

D says objects like glass, wouldn't that be wrong because of that. But possibly correct if it said objects like water

Answer 16

if the statement "electromagnetic waves get closer together when they go through dense media like glass" means the concept illustrated by means of the drawing of @rvc, then also option D is correct!

Answer 17

Ok.

Answer 18

I remember that, the refractive index of glass is about \(1.3\) which is greather than the refractive index of air, which is about \(1\)

Answer 19

ok so B and D are both correct?

Answer 20

air is rarer in this case

Answer 21

glass is denser

Answer 22

brb

Answer 23

yes! nevertheless I think that the meaning of "electromagnetic waves get closer together when they go through dense media like glass" means that the wavefronts get closer together? That is my doubt!

Answer 24

Yeah

Answer 25

badly written question

Answer 26

in that case also option B is the right option!

Answer 27

yeah i agree its a very poorly written question

Answer 28

sorry, I meant this:
in that case only option B is the right option!!

Answer 29

ok

Answer 30

it appears broken because the light appears to change direction and not even that is a causal explanation

the actual reason has something to do with QCD......

Answer 31

yeah i know, thats why i posted this question because i didnt understand how it had to do with the answers

Answer 32

I think with QED, am I right? @IrishBoy123

Answer 33

why should light change direction just because it gets faster. why should it appear to take the path of least time. these are all still observations and i do not see how the word "because" appear in the question

michele - C for chromo, i have a Feynman book that i don't understand....on this :-))))

Answer 34

but yes, QED.....is the bigger subject that i also don't understand :-)))

Answer 35

lol :) @IrishBoy123 I think you will be a good physicist one day!!

Answer 36

thank you maestro!!

Answer 37

:)

Answer 38

@mdjjh16 you got your answer yet

my vote on this question is "haven't a clue what the question actually wants ..... soz :-(

Answer 39

im going with B

Answer 40

if i had to, i'd go B too

Answer 41

thanks for the help

Answer 42

here is my textbook on standard model which I have studied at university, it is very simple to read and it develops both QED and QCD:
\[\begin{gathered}
{\text{D}}{\text{.}}\;{\text{Griffiths}} \hfill \\
{\mathbf{Introduction}}\;\;{\mathbf{to}}\;\;{\mathbf{Elementary}}\;\;{\mathbf{Particles}} \hfill \\
{\text{J}}{\text{.}}\;{\text{Wiley}} \hfill \\
\end{gathered} \]
@IrishBoy123

Answer 43

cheers michele, i'm definitely going to hunt that down.

Answer 44

ok! :)