# When the screen is moved away from plane of slits in YDSE then the effect on interference fringes is

(a) Angular separation of fringes increases but linear separation or fringe width decreases

(b)Angular separation of fringes remains constant but the linear separation or fringe width increases

(c) Both remains constant

(d)None

When screen is moved away from plane of slits then the angular separation $(=\large \frac{\lambda}{d})$ of fringes remains constant.
But the linear separation or fringe width increase in proportion to distance (D) from screen .
Hence b is the correct answer.