A screen used in a Young's double-slit experiment extends from y = −4.2β to y = +4.2β, where β is the fringe width. How many bright fringes are visible on the screen?
Physics · Wave Optics · young's dubble slit experiments
JEE Mains NEET JEE Advanced

Question

A screen used in a Young's double-slit experiment extends from y = −4.2β to y = +4.2β, where β is the fringe width. How many bright fringes are visible on the screen?

G1 Physics · Accepted Answer

Bright fringes occur at y = mβ. The condition |m| ≤ 4.2 allows m = −4, −3, −2, −1, 0, 1, 2, 3, 4. Thus there are 9 bright fringes. Hence the answer is 9.