In Young's double slit experiment performed using a monochromatic light of wavelength $$\lambda$$, when a glass plate ($$\mu$$ = 1.5) of thickness x$$\lambda$$ is introduced in the path of the one of the interfering beams, the intensity at the position where the central maximum occurred previously remains unchanged. The value of x will be :

The refracting angle of a prism is A and refractive index of the material of the prism is cot (A/2). Then the angle of minimum deviation will be -

The aperture of the objective is 24.4 cm. The resolving power of this telescope, if a light of wavelength 2440 $$\mathop A\limits^o $$ is used to see th object will be :

A convex lens has power P. It is cut into two halves along its principal axis. Further one piece (out of the two halves) is cut into two halves perpendicular to the principal axis (as shown in figures). Choose the incorrect option for the reported pieces.