To solve this problem we will apply the concept related to destructive interference (from the principle of superposition). This concept is understood as a superposition of two or more waves of identical or similar frequency that, when interfering, create a new wave pattern of less intensity (amplitude) at a point called a node. Mathematically it can be described as

Where,
d = Path difference
= wavelength
n = Any integer which represent the number of repetition of the spectrum
In this question the distance between the two source will be minimum for the case of minimum path difference, then n= 1



Therefore the minimum distance that should you separate two sources emitting the same waves is 2.5mm
Explanation:
Using Kinematics,
we have a = (v - u) / t.
Therefore a = (36m/s - 22m/s) / 5s = 2.8m/s².
Solution :
Given :
Rectangular wingspan
Length,L = 17.5 m
Chord, c = 3 m
Free stream velocity of flow,
= 200 m/s
Given that the flow is laminar.



So boundary layer thickness,


= 0.0024 m
The dynamic pressure, 


The skin friction drag co-efficient is given by


= 0.00021


= 270 N
Therefore the net drag = 270 x 2
= 540 N
A device employing a lens, shutter, and persistent light source that projects images from glass slides onto a flat white wall or cloth drape hung in the dark is image projection began with the MAGIC LANTERN
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Explanation:</u></h3>
The magic lantern works on the sliding runner technology. The image can be made larger in size and can be projected with the help of an optical device. When the technology of motion toy become older, this magic lantern is the modernized version of the motion toy technology. The modernization of the magic lantern was as an alternative of to motion-toy technology.
The photos and images that are taken can be increased in the size and projection can be made. These images can be enlarged in size by the help of a photographic images. this helps in image and also in taking photographs. This photographic image can be attached with Magic lantern. A long slide of glass helps in projecting the image on the walls or cloth drapes using magic lantern. This gives life to Shadows.