A concave mirror of radius of curvature 10 cm is cut into two equal parts, slightly separated and placed in front of a monochromatic line source S of wavelength 2000 ^A as shown in figure. Consider only interference in reflected light after first reflection from mirrors. Assume direct light from S is blocked from reaching the screen
Assume A is the position of first order maxima on the screen. Now the point object is moved away from normal to screen with constant speed, then: