Constants light of wavelength 640 nm falls on two slits and produces an interference pattern in which the third-order bright red fringe is 46 mm from the central fringe on a screen 2.6 m away. what is the separation of the two slits?
express your answer to two significant figures and include the appropriate units.

1.1 × 10⁻⁴ m =  0.11 mm

Explanation:

d y / L = m λ is the formula that relates the slit separation with all other given quantities here.

y = fringe width =  46 mm = 0.046 m

L = distance to the screen = 2.6 m

Wavelength = λ = 640 nm

Order of the fringe = m = 3

Slit separation = d = m λL / y = (3)(640 × 10⁻⁹ )(2.6) /0.046

                                              = 1.1 × 10⁻⁴ m =  0.11 mm

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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