If the 5,500 J of sound and light is the ONLY useful output
from the phone, then the phone's efficiency is
(5,500J / 10,000J) = 0.55 = 55% .
But the test engineer forgot one little minor almost insignificant detail.
As a test engineer myself, I'd say that he needs to turn in his laptop
and soldering iron, and think about changing his career to a job for
which he may be better suited, like 8 hours a day in a highway toll-booth.
What about that little radio transmitter and receiver inside the phone,
that maintain digital RF communication with the nearest cell tower ?
Without that microscopic radio transceiver ... plus 30 or 40 apps
that are always running unless you shut them off ... the device in your
pocket is essentially a flat rock with one side that sometimes glows.
It makes an echo and it circles around it.
The speed of an object is measured by calculating the distance it travels per unit time.
The formula in Physics for calculating speed is = distance/ time.
Since an object at rest is not covering any distance, the speed is always assumed to be 0 m/s.
Answer:
Refraction
Explanation:
When light passes from a rarer medium into a denser medium, it bends in the medium away from the normal. This creates the phenomenon of "apparent depth" as given in the question.
