There are actually two different kinds of mirrors, and the answer is different
for each one.
-- Plain old everyday hand mirror, vanity mirror, bathroom mirror, makeup
mirror, etc.
Opaque, reflecting silver coating is on the back of the glass.
Light from your tongue or your teeth flows to the front surface of the glass,
through the glass, out of the back surface of the glass, bounces off of the silver
coating on the back, reverses its direction, enters the back surface of the glass,
comes back through the glass again, leaves the front of the glass, goes into your
eyes, and you can see your teeth or your tongue.
Both surfaces of the glass, as well as the glass in between the surfaces, are
transparent. The silver coating on the back is opaque. I know that, because
when I look at the back of a mirror, I can't see any light coming through it.
The coating on the back is also reflective ... a big part of the reason why
a mirror works.
-- Expensive mirrors used by astronomers and eye-doctors.
Known as "first surface" mirrors.
Opaque, reflecting silver coating is on the <em>front</em> of the glass.
Light
from your tongue or your teeth flows toward the front surface of the glass,
but never actually gets there. It bounces off of
the silver coating on the front of
the glass, reverses its direction, goes into your eyes, and you can see your teeth
or
your tongue.
The glass is transparent, but that doesn't matter, because the light never reaches
the glass. It only goes as far as the opaque silver coating on the front, and is
reflected from there.
Answer:
The unit for power is the Watt
Answer:
10. B
13. It's actually 30 seconds but 20 comes closest so B
14. B, any type of stretching is good before you perform any type of physical activity because it loosens up the muscles
15. D, all of the above
Explanation:
I have done many sports in my life and am still very active, I grew to know most of these things through the years.
Answer:
The average emf that will be induced in the wire loop during the extraction process is 37.9 V
Explanation:
The average emf induced can be calculated from the formula
Where is the number of turns
is the change in magnetic flux
is the time interval
The change in magnetic flux is given by
Where is the final magnetic flux
and is the initial magnetic flux
Magnetic flux is given by the formula
Where is the magnetic field
is the area
and is the angle between the magnetic field and the area.
Initially, the magnetic field and the area are pointed in the same direction, that is,
From the question,
B = 1.5 T
and radius = 15.0 cm = 0.15 m
Since it is a circular loop of wire, the area is given by
∴
∴
( NOTE: )
Wb
For
The field pointed upwards, that is . Since
Then
Hence,
From the question
Here, = 1
Hence,
becomes
Hence, the average emf that will be induced in the wire loop during the extraction process is 37.9 V.
Answer:
Energy lost due to friction is 22 J
Explanation:
Mass of the ball m = 4 kg
Initially velocity of ball v = 6 m/sec
So kinetic energy of the ball
Now due to friction velocity decreases to 5 m/sec
Kinetic energy become
Therefore energy lost due to friction = 72 -50 = 22 J