Answer
Given,
Periscope uses 45-45-90 prisms with total internal reflection adjacent to 45°.
refractive index of water, n_a = 1.33
refractive index of glass, n_g = 1.52
When the light enters the water, water will act as a lens and when we see the object from the periscope the object shown is farther than the usual distance.
Sunlight (white light) refracts through droplets of water in the atmosphere and this causes a rainbow in the sky. The correct option among all the options that are given in the question is the third option or option "C". The rainbow is caused by the reflection, refraction and dispersion of sunlight in water droplets that are present in the atmosphere.
The wavelength of the light beam required to turn back all the ejected electrons is 497 nm which is option (b).
- Work function is a material property defined as the minimum amount of energy required to infinitely remove electrons from the surface of a particular solid.
- The potential difference required to support all emitted electrons is called the stopping potential which is given by
.....(1) - where
is the stopping potential and e is the charge of the electron given by 
.
It is given that work function (Ф) of monochromatic light is 2.50 eV.
Einstein photoelectric equation is given by:
....(2)
where K.E(max) is the maximum kinetic energy.
Substituting (1) into (2) , we get
As we know that 
....(3)
where Speed of light,
and Planck's constant , 
From equation (3) , we get
Learn about more einstein photoelectric equation here:
brainly.com/question/11683155
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Answer: the effective design stiffness required to limit the bumper maximum deflection during impact to 4 cm is 3906250 N/m
Explanation:
Given that;
mass of vehicle m = 1000 kg
for a low speed test; V = 2.5 m/s
bumper maximum deflection = 4 cm = 0.04 m
First we determine the energy of the vehicle just prior to impact;
W_v = 1/2mv²
we substitute
W_v = 1/2 × 1000 × (2.5)²
W_v = 3125 J
now, the the effective design stiffness k will be:
at the impact point, energy of the vehicle converts to elastic potential energy of the bumper;
hence;
W_v = 1/2kx²
we substitute
3125 = 1/2 × k (0.04)²
3125 = 0.0008k
k = 3125 / 0.0008
k = 3906250 N/m
Therefore, the effective design stiffness required to limit the bumper maximum deflection during impact to 4 cm is 3906250 N/m
