A. Suppose the laser light has wavelength 400 nm, and that the two small slits, which act as point sources of light, are separated by 0.1 mm. (Recall that 1 nm = 10-9 meters.) Approximately how many nodal lines would be present in the pattern of overlapping light waves when the laser light emerges from the two slits in the mask?

200 nodal lines

Explanation:

To find the number of lines you first use the following formula for the condition of constructive interference:

 (1)

d: distance between slits = 0.1mm = 0.1*10^-3 m

θ: angle between the axis of the slits and the m-th fringe of interference

λ: wavelength of light = 400 nm = 400*10^-9 m

You obtain the max number of lines when he angle is 90°. Then, you replace the angle by 90° and solve the equation (1) for m:

hence, the number of lines in the interference pattern are 200

f=ma newton

f=100x2.5=250n