A monochromatic plane wave of speed c and wavelength λ is diffracted at a small aperture. The diagram illustrates successive wavefronts. After what time will some portion of the wavefront X Y reach P ?

Question

A monochromatic plane wave of speed c and wavelength λ is diffracted at a small aperture. The diagram illustrates successive wavefronts. After what time will some portion of the wavefront X Y reach P ? (A) (3 λ/2 c) (B) (2 λ/c) (C) (3 λ/c) (D) (4 λ/c)

Tardigrade Admin · Accepted Answer

The gap between successive wavefronts is λ. Here t=((3 λ)/c).

Q. A monochromatic plane wave of speed $c$ and wavelength $λ$ is diffracted at a small aperture. The diagram illustrates successive wavefronts. After what time will some portion of the wavefront $X Y$ reach $P$ ?

$\frac{3 λ}{2 c}$

$\frac{2 λ}{c}$

$\frac{3 λ}{c}$

$\frac{4 λ}{c}$

The gap between successive wavefronts is $λ$ . Here $t = \frac{( 3 λ )}{c}$ .

Q. A monochromatic plane wave of speed c and wavelength λ is diffracted at a small aperture. The diagram illustrates successive wavefronts. After what time will some portion of the wavefront XY reach P ?

2c3λ​

c2λ​

c3λ​

c4λ​