MCQ
Two incident monochromatic waves whose wavelengths differ by a small amount $d\lambda$ are separated angularly at $\theta$ and $\theta + d\theta$ $w.r.t$. the incidence ray. The dispersive power is given by
- A$d\theta /\theta$
- ✓$d\theta /d\lambda$
- C$d\lambda /\lambda$
- D$\lambda (d\lambda /d\theta )$
