Question

Listed below are alterations made, one at a time, to the original experiment, and the experiment is repeated. after each alteration, the experiment is returned to its original configuration. which of these alterations decreases the angles at which the diffraction minima appear

Answer 1

Answer : The question is incomplete, full question is attached in the answer.

The equation that will be applicable to given situation will be as;

d X sinΘ = m X λ; 

Here, d will be the slit width,
Θ will be the angle of the minima,
m will be the order of the minima,
and λ will be the wavelength of the light. 

Now we have to find Θ, On rearranging the equation we get it as; Θ = arc sin( m X λ / d ) 

In the given condition of A when the d increase the argument increases with the angle of Θ;

In case of B it seems to be irrelevant, as changing the distance to the screen will not affect the distance between the diffraction angle of minima, it will only change its width;

In case of C the angle of Θ decreases, as we decrease the argument the d value also decreases;

In D it compensates to decrease the λ and hence the Θ also decreases;

In E when it is observed in water, the light's frequency remains to be the same, but it speed of the light ray slows down, so the wavelength gets smaller. So, it will decrease the dispersion angle of minima;

In F it seems to irrelevant as it will not change the angle of dispersion.