<span>Shading.
When light hits an opaque surface some is absorbed, the rest is reflected, The reflected light is called shading. Reflection is not simple and varies with material.
The surface’s structure defines the details of reflection. Variations produce anything from bright specular reflection</span>
Given mass= 1kg
Weight on earth = mg(gravity of earth) = 9.8N
weight on moon = mg(gravity of moon)= 1.62N
weight on outer space mg(gravity outer space = 0) = 0N
To solve this problem it is necessary to take into account the concepts related to frequency and period, and how they are related to each other.
The relationship that defines both agreements is given by the equation,
Then the frequency for the previous period given (2sec) is
The beat frequency of two frequencies is equal to the difference between the two frequencies, then
<em>Hence option A is incorrect.</em>
We can do this process for 254Hz as 
and 258 Hz for 
, then
<em>Hence option B is incorrect. </em>
We can also do this process for 255Hz as and 257 Hz for , then
<em>Hence option C is incorrect. </em>
We can also do this process for 255.5Hz as f_1 and 256.5 Hz for f_2, then
<em>Hence option D is incorrect. </em>
We can also do this process for 255.75Hz as and 256.25 Hz for , then
<em>Hence option E is incorrect. </em>
Therefore the sum of the frequencies in the sound wave would be 256.25Hz and 255.75Hz
The Ideal Gas Law makes a few assumptions from the Kinetic-Molecular Theory. These assumptions make our work much easier but aren't true under all conditions. The assumptions are,
1) Particles of a gas have virtually no volume and are like single points.
2) Particles exhibit no attractions or repulsions between them.
3) Particles are in continuous, random motion.
4) Collisions between particles are elastic, meaning basically that when they collide, they don't lose any energy.
5) The average kinetic energy is the same for all gasses at a given temperature, regardless of the identity of the gas.
It's generally true that gasses are mostly empty space and their particles occupy very little volume. Gasses are usually far enough apart that they exhibit very little attractive or repulsive forces. When energetic, the gas particles are also in fairly continuous motion, and without other forces, the motion is basically random. Collisions absorb very little energy, and the average KE is pretty close.
Most of these assumptions are dependent on having gas particles very spread apart. When is that true? Think about the other gas laws to remember what properties are related to volume.
A gas with a low pressure and a high temperature will be spread out and therefore exhibit ideal properties.
So, in analyzing the four choices given, we look for low P and high T.
A is at absolute zero, which is pretty much impossible, and definitely does not describe a gas. We rule this out immediately.
B and D are at the same temperature (273 K, or 0 °C), but C is at 100 K, or -173 K. This is very cold, so we rule that out.
We move on to comparing the pressures of B and D. Remember, a low pressure means the particles are more spread out. B has P = 1 Pa, but D has 100 kPa. We need the same units to confirm. Based on our metric prefixes, we know that kPa is kilopascals, and is thus 1000 pascals. So, the pressure of D is five orders of magnitude greater! Thus, the answer is B.
Answer:
Night vision is the ability to see in low-light conditions. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range.
