Question

Physics Questions 4

Answer 1

I was using the formula Ep=Ek , q(V/d)= 1/2mv^2 , but not getting the answer anything wrong ? @Evoker

Answer 2

@osprey

Answer 3

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elewor.html
\[\large W = q \Delta V = \Delta KE\]since the final speed is zero\[\large q \Delta V = \frac{ 1 }{ 2 } m v^2 \]plug in the charge of an alpha (2 times electron), and the mass (4 times the atomic mass unit)\[\Large 2(1.602*10^{-19}) (1.2*10^2) = \frac{ 1 }{ 2 } (6.64×10^{−27}) v^2 \]

Answer 4

thats what I did didnt get the answer

Answer 5

I got 3 somthing that is not matching any of the choices

Answer 6

what you get ?

Answer 7

You must have done some math wrong...

http://www.wolframalpha.com/input/?i=2(1.602*10%5E%7B-19%7D)+(1.2*10%5E2)+%3D+%5Cfrac%7B+1+%7D%7B+2+%7D+(6.64%C3%9710%5E%7B%E2%88%9227%7D)+v%5E2

Answer 8

Oh yea! lol sorry

Answer 9

lol no prob :)

Answer 10

Your original formula was wrong, though: q(V/d)= 1/2mv^2 there should be no d, just qV.

Answer 11

oh so the distance they give is just an distraction ?

Answer 12

Yep :)

Answer 13

can you help me with this one

Answer 14

Light travels slowest through the highest refractive index

Answer 15

i'll get that to later but this other I just have no idea

Answer 16

any idea?

Answer 17

Different wavelengths refract to different angles. Remember the Pink Floyd album cover... http://ep.yimg.com/ay/pandorasboxoc/pink-floyd-dark-side-of-the-moon-tapestry-wall-hanging-1.gif

As for the last "Light travels slowest through the highest refractive index "

just choose the highest index - glass at 1.5 - is the slowest

Answer 18

should I just memorizr this ?

Answer 19

oh its not B beacuse its refracts straight lines not defracts (waves) right ?

Answer 20

Yes, it's A. Refract, not diffract.

Answer 21

Ok this one I am confused they just give one thing

Answer 22

Do you wanna see the formula sheet ? that I use ?

Answer 23

or you knwo the formulas ?

Answer 24

Sure.

I think it's \(\large E = hf\) you need to use first... The E would be the given value for silicon, h is plancks constant, f is frequency.

Then use \(\large c = f \lambda \)

Answer 25

oh beacuse my formila sheet says W= E ? so E and W same thing ?

Answer 26

Yeah, remember that work done is equal to energy expended or supplied or w/e.

Answer 27

wow okey yea got it ! thank you!

Answer 28

Welcome!

Answer 29

also I was still confused about the physics pricipls quesiton like when thy ask you what the pricnicplas are used in this question how to comnbat that?

Answer 30

Yeah those ones are a little annoying, really. I don't really have a good way to explain it. Just try to figure out how you'd solve it, then try to match your method with things on the list of principles.

Answer 31

hey u there can help me with another ?

Answer 32

sure, post a new question though

Answer 33

I think you just need to convert the units TeV to J.

Answer 34

wow that easy! I always get confused thinking I have to use some kind of a formula!

Answer 35

haha i thought so at first too... but eV are a unit of energy. Tera is... idk i forgot but google will know.

Answer 36

T is \(\large 10^{12}\) and then just plug in the electron charge \(\large 1.602*10^{-19}\)

Answer 37

An alpha particle is a helium nucleus. It has two positive charges. It has a nuclear mass of 4 protons. It has an initial kinetic energy of “half m v squared” as is often said. The field between the plates works against this kinetic energy, and decelerates the particle to zero speed.
The principle of conservation of energy can be used in the form that the work energy supplied by the field between the plates is used to work to decelerate and thus convert the kinetic energy of the moving alpha particle.
A load of number crunching later and the answer turns out to be
A
I've enclosed the grinding calculation in a powerpoint show as per. I wonder how many marks the question is worth ... I also wonder whether it would be worth everyone's while just to find away of uploading the entire paper you're looking at, constants, and marks and all.

Answer 38

can you help me with this one ?

Answer 39

Time to make a brand new question @KittyKat as this is long enough

Answer 40

yea sure