This problem must be solved using a sketch. I attached an illustration of the problem.
You must trace the ray that reflects from the top off the table to your eyes. This how eyesight works, light rays reflects off the objects into your eyes.
Law of reflection tells us that light ray reflects off the surface at the same angle in which it falls on it( i attached another illustration of this).
Now we can write tangens equations:

We solve for h:
Answer: send the message underwater because a more dense medium would make the sound travel faster.
Explanation:
Dolphins communicate using compression waves - longitudinal waves. Longitudinal waves requires a medium to travel. A longitudinal wave transfers energy by the vibration of medium particles in the direction of the wave motion. Compression are the regions where density of the medium is higher and rarefaction is a low density region.
A longitudinal wave travels faster in a denser medium. It has maximum speed in solid and minimum in gas. Thus, to transfer message quickly to dolphin B., dolphin A should send the message underwater and not in air. This is because water has higher density than air. Molecules collide more quickly in water than in air and it takes less time for signal to travel.
The answer would be B. Magnetic fields are invisible they cannot be directly observed
Answer:
26036485.6433 W/m²
Explanation:
E= Energy = 470 J
t = Time = 4 seconds
d = Diameter = 2.6 mm
Power is given by

Intensity is given by

The intensity of the laser beam is 26036485.6433 W/m²
Answer:
See the explanation below
Explanation:
The pressure is defined as the product of the density of the liquid by the gravitational acceleration by the height, and can be easily calculated by means of the following equation.

where:
Ro = density of the fluid [kg/m³]
g = gravity acceleration = 9.81 [m/s²]
h = elevation [m]
In this way we can understand that the greater pressure is achieved by means of the height of the liquid, that is, as long as the fluid has more height, greater pressure will be achieved at the bottom.
Therefore in order of decreasing will be
The largest pressure with the largest height of the liquid, container B. The next is obtained with container D, the next with container A and the lowest pressure with container C.
The pressure decreases as we go from the container B - D - A - C