IIT JEE , AIEEE Forum - Physics , Mechanics

tarun_bits

i saw the wave equation in NCERT as..

y= A sin( kx - wt)

in some other books ..i saw it as

y= A sin (wt - kx)

is there a difference between the two

LAMPARD

See,y=Asin(kx-wt)=-Asin(wt-kx)...
the only diff. is that amplitude in the 2 cases is A and -A...
A is max.amplitude in +ve y and -A in -ve y...so it dusnt really make a diff. how u write the eqn...hope u got it...

stavan110

what lampard says is true.....

well the only thing we have to make sure is that frequency comes with time and k(wave vector ) with x

suresan

The physical significance is that
y = A Sin (kx _ wt) propogates towards the Negative x direction
and y = A Sin (wt _ kx) propogates towards positive x direction

anchitsaini

there would be a phase difference between the two waves
=(wt-kx-kx+wt)=2(wt - kx)

suresan
u are (edited) probably wrong as both the waves are propagating in the same direction ie the positive x direction(from my knowledge)

y=asin(wt+kx)
would propagate in the negative x direction

suresan

i am sorry, You got it right, thank you, some times i do get confused

coolvignesh

hey hang on guyz....
i think u didnt look it from another angle.....
there is a phase difference of pi b/w both the waves...
as -ve of sintheta is sin(theta +pi)

tarun_bits

but as from lampards explanation
the phase difference should be of pie...as one is negative and other positive

tarun_bits

u are correct cool vignesh

tarun_bits

combinig both the reasons..

pie = 2 (wt - kx)

pie / 2 + kx = wt

what is that...

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