Question

For two waves of equal intensity \[I_0\], which expression gives the resultant intensity?

Options

• \[I=4I_0\cos^2\left(\frac{\phi}{2}\right)\]

• \[I=2I_0\cos^2\left(\frac{\phi}{2}\right)\]

• \[I=4I_0\cos^2\left(\phi\right)\]

• \[I=2I_0\]

Answer 1

For two waves of equal intensity \[I_0\], the resultant intensity is \[I=4I_0\cos^2\left(\frac{\phi}{2}\right)\]. The phase difference \[\phi\] determines whether the interference is constructive or destructive.