IIT JEE , AIEEE Forum - Physics , Mechanics

vish0001

what is the amplitude of the plane progressive wave

y = 6 sin (

x/3) cos ( 40

t )

balaze90

i think its 3
whats the ans?

joyfrancis

3 is right.
Equation of a standing wave is
2A(sinkxcos(omega)t)

vish0001

ya......me too got the same answer.....

please try these also

1. what is the distance between two particles on a plane progressive wave which has a wave velocity of 300 m /s , frequency = 500 Hz and the phase difference between the particles is 60 degrees

2. 8 guests are invited by a husband and wife......all the guests sit in a single line. what is the probability that the husband and wife sit with each other ?

my approach to this second one please see

if we take the husband and wife as a one unit
then total number of persons become 9
this means
total ways of arranging the people in the line = 9 P 9 X 2 ! { as the husband and

wife can be permuted in 2 ! ways}

total ways of arranging = 10 !

=> probablity = 9 ! X 2 / 10 !

but this is not giving the correct answer

plese see

vish0001

yaar try this one na pls

joyfrancis

Hi.

Phase difference at any instant = k*d

k=2pi/lambda

lambda=v/f=3/5

so,

pi/3 = 10d*pi/3

d=0.1m

vish0001

thanks yaar

pls look at the second one also pls

vish0001

second one plss

akku

I think that ur ans to the second one is correct if "the guests sit along wid the husband and wife in a str line" But pls type the exact language of the question(u have used ...... in the first line) May be only 8 people r to be seated ! In that case PROBABILITY=7!2! 8C6*/10C8*8!

vish0001

ya think most probably there is a misprint
thanks yaar for the answer

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