Question

If we have a red laser and we shine in through two narrow slits we get a pattern of bright and dark fringes on a screen.
If we want the bright fringes to be formed at a bigger angle from the center, what could we do to make this happen?

• A. Move the screen closer
• B. Move the screen further away
• C. Use slits that are closer together
• D. Use slits that are further apart
• E. Make the laser brighter

Answer 1

The correct option is C Use slits that are closer together

Angle made by nth bright fringe, $sin{\theta }_n=\frac{n\lambda }{d}$

$⟹$ ${\theta }_n\propto \frac{1}{d}$

Thus using the slits that are closer together would make the nth bright fringe at larger angle from the center.

Hence option C is correct.