In Young's double slit experiment, the intensity on the screen at a point where path difference is λ is K. What will be the intensity at the point where path difference is λ/4?

By using phase difference ϕ=2πλ(Δ)For path difference λ, phase difference ϕ1=2π and for path difference λ/4, phase difference ϕ2=π/2.Also by using I=4I0cos2ϕ2⇒I1I2=cos2ϕ1/2cos2ϕ2/2⇒KI2=cos2(2π/2)cos2π/22=11/2⇒I2=K2