Answer:
The smallest film thickness is 117 nm.
Explanation:
Light interference on thin films can be constructive or destructive. Constructive interference is dependent on the film thickness and the refractive index of the medium.
For the first interference (surface nearest to viewer), the minimum thickness can be expressed as:

where n is the refractive index of the bubble film.
Therefore,


∴ 

1 watt = 1 joule/sec
1800 watts = 1800 joules/sec
(1800 J/sec) x (20 min) x (60 sec/min)
= (1800 x 20 x 60) joules = 2,160,000 joules .
( 2.16 megajoules )
Answer:
amplitude
Explanation:
wave is a called the crest, and the low point is called the trough. For longitudinal waves, the compressions and rarefactions are analogous to the crests and troughs of transverse waves. The distance between successive crests or troughs is called the wavelength. The height of a wave is the amplitude.…