Two plane mirrors are inclined to each other such that a ray of light incident on the first mirror (M₁) and parallel to the second mirror (M₂) is finally reflected from the second mirror (M₂) parallel to the first mirror (M₁). The angle between the two mirrors will be :

In a Young's double slit experiment, the slits are placed 0.320 mm apart. Light of wavelength $$\lambda $$ = 500 nm is incident on the slits. The total number of bright fringes that are observed in the angular range $$-$$ 30^o$$ \le $$$$\theta $$$$ \le $$30^o is :

A parallel plate capacitor with square plates is filled with four dielecytrics of dielectrics constants K₁, K₂, K₃, K₄ arranged as shown in the figure. The effective dielectric constant K will be :

The position co-ordinates of a particle moving in a 3-D coordinate system is given by
x = a cos$$\omega $$t
y = a sin$$\omega $$t and
z = a$$\omega $$t

The speed of the particle is :