There would be no light at night foe nocturnal animals
Well, my German isn't as sharp as it used to be, but it looks like you're supposed to use the symbols at the top and draw two circuits ... one where the switch is closed and the light is shining, the other where the switch is open and the light is out.
That should be pretty easy for you. Just hook up one battery, one switch, and one light, all in series. Then opening and closing the switch makes the light go on and off.
Answer
Given,
refractive index of film, n = 1.6
refractive index of air, n' = 1
angle of incidence, i = 35°
angle of refraction, r = ?
Using Snell's law
n' sin i = n sin r
1 x sin 35° = 1.6 x sin r
r = 21°
Angle of refraction is equal to 21°.
Now,
distance at which refractive angle comes out
d = 2.5 mm
α be the angle with horizontal surface and incident ray.
α = 90°-21° = 69°
t be the thickness of the film.
So,


t = 2.26 mm
Hence, the thickness of the film is equal to 2.26 mm.
Violet : The shortest wavelengths are perceived as violet and the longest wavelengths are perceived as red.<span />
Sum of the first ten digits is:
7+3+4+5+4+1+7+8+0 = 39
39, when divided by 9 give you the remainder of 3
9 x4, is 36
36 +3 equals 39
(39 = 9 x 4 + 3)
So X= 0