A wave disturbance in a medium is described by `y(x,t) = 0.02 "cos"(50pit + (pi)/(2))"cos"(10pix)` where x and y are in metre and t is in second . Which of the following is correct ?

Options

A. A, C and D
B. A, B and C
C. A and B only
D. A, B, C and D

Answer

D

Explanation

`y=0.02cos[50pit+pi/2].cospix`
A) `R=0.02cos10pix`
`=0.02cos10pixx0.15`
`=0.02cos1.5pi`
`=0.02cos(pi+pi/2)`
`=0.02sin pi/2 = 0.02xx0 = 0`
B) `R=0.02cos10pix`
`=0.02cos 10pixx0.3`
`=0.02cos3pi`
=0.02m
C) `v =omega/k = (50pi)/(10pi) =5` m/s
D) k=10k
`(2pi)/(lamda) = 10pi therefore lamda = 0.2m`
All of the above are correct .