The answer here would be infrared waves. Hot objects and humans give off heat in the form of infrared light, thermal imaging technology in the goggles enable them to catch this light emitted by these objects
To solve this problem it is necessary to use the concepts related to Snell's law.
Snell's law establishes that reflection is subject to
Where,
Angle between the normal surface at the point of contact
n = Indices of refraction for corresponding media
The total internal reflection would then be given by
Therefore the 
would be equal to
Therefore the largest value of the angle α is 30.27°
Answer:
20.5s
Explanation:
Given parameters:
Distance = 30m
Unknown:
Time = ?
Solution:
The time it will take to hop a distance of 30m using the speed for the 5m trial is the duration of the trip.
The speed for the 5m trial = 1.46m/s
Now;
Speed = 
Distance = speed x time
time = 
Input the parameters and solve;
time = 
= 20.5s
Answer: wave
Explanation:
These are the basic definitions and characteristic of the terms given, which show tha the only rigth answer is the second option: wave.
1) Force is an interaction. There are four natural forces: electrostatic, gravity, strong nuclear force and weak nuclear force.
2) Wave: is a sequence of pulses or vibrations that cause the continuous transportation of energy (propagation). There is not transport of mass, only energy.
Some examples of waves are sound waves, electromagnetic waves (light, radio waves, micro waves, infrarred waves, ultraviolet waves).
3) Vacuum: is the absence of matter; empty space. Only electromagnetic waves can travel through vacuum; other waves need a medium to travel.
4) Medium: any matter is a medium: a solid, the air, a liquid, all of them are media through which waves can transport its energy, depending of the wavelength.
