Answer:
3. Farther apart for red light
Explanation:
The distance [tex]y[/tex] between fringes is
[tex]y = \dfrac{\lambda L }{d},[/tex]
where [tex]\lambda[/tex] is the wavelength of light, [tex]L[/tex] is the distance to the screen, and [tex]d[/tex] is the slit separation.
Now, the wavelength [tex]\lambda_r[/tex] of the red light is greater than for the wavelength [tex]\lambda_b[/tex] for blue light:
[tex]\lambda_r> \lambda_b[/tex],
which means
[tex]\dfrac{\lambda_r L }{d}>\dfrac{\lambda_b L }{d},[/tex]
In other words, the distance between the fringes is greater for red light, which from the options is choice 3.
