<span>A linearly polarized electromagnetic wave has an average intensity of 450 W/m2. This wave is directed towards two ideal polarizers (in real polarizers, transmission is also effected by reflection and absorption). Polarizer A is oriented with its transmission axis at an angle of θ1 = 32.6° with the incident electric field. Polarizer B has its axis at an angle of θ2 = 75.8° with the incident electric field, as shown in the figure.</span>
Answer:
2.62seconds
Explanation:
Echo occurs when sound reflects and causing a delay before getting to the listener.
Let x be the distance from between the source and the reflector
t be the time taken for the echo to occur
v be the velocity of sound in air.
Using the relationship 2x = vt
t = 2x/v
Given x = 450metres
v = 343m/s
t = 2(450)/343
t = 900/343
t = 2.62seconds
It will take 2.62 seconds for him to hear his own voice echo off of the wall.
A machine can never be 100% efficient because some work is always lost
due to the lack of materials or equipment that would convert work by 100%. It follows
the second law of entropy. The ideal engine is known as Carnot’s engine having
a 100% efficiency. So far, no engine has ever gotten to 100%.