Light from two coherent sources of the same amplitude A and wavelength `lambda` illuminates the screen. The intensity of the central maximum is `I_(0)`. If the sources were incoherent, the intensity at the same point will be

Options

A. `4I_(0)`
B. `2I_(0)`
C. `I_(0)`
D. `(I_(0))/(2)`

Answer

D

Explanation

If sources are coherent,
`I_(R)=I_(1)+I_(2)+2sqrt(I_(1)I_(2))cosphi`
` :.I_(0)=I+I+2Icos0^(@)=4I`
If sources are incoherent, `I_(R)=I_(1)+I_(2)=2I =(4I_(0))/(2)=(I_(0))/(2)`