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.
Answer: B. store electric charges.
Explanation: I JUST TOOK THE PF EXAM AND I GOT IT CORRECT!!!!
Answer:

Explanation:
In this process energy must be conserved. On the initial stage, there will be only gravitational potential energy, while on the final stage there will be only elastic potential energy, so they will be equal. We write this as:

Which is the same as:

So we can obtain our mass from there, and for our values:

A). It takes air in from outside the body.