Adouble-slit diffraction pattern is formed on a distant screen. if the separation between the slits decreases, what happens to the distance between interference fringes? assume the angles involved remain small.

the effect cannot be determined unless the distance between the sits and the screen is known.
the distance between interference fringes increases.
the distance between interference fringes remains the same.
the distance between interference fringes also decreases.

The distance between interference fringes increases.

Explanation:

In a double-slit diffraction pattern, the distance of the n-order fringe from the centre of the pattern is

where is the wavelength of the light, D the distance of the screen, and d the separation between the slits.

If we take two adjacent fringes, n and (n+1), their distance is

so, we see that it is inversely proportional to the slit separation, d.

Therefore, if the separation between the slits decreases, the distance between the interference fringes increases.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me