There are 92 natural ones and about 20 more made in particle-Physics labs.
If we only stick to the 92 natural ones, then there are
(92!) / (88! times 4!) = 2,794,155 possible answers to your question.
Here's one: Osmium
Neodymium
Iridium
Gold .
Answer:
gravity pulls the falling object to the ground
Explanation:
Efficiency of heat engine is determined by the ratio of difference in temperature of cold from hot reservoir to the temperature of hot reservoir over temperature of hot reservoir.
Answer:

Explanation:
Given:
Length of cylinder is, L = 0.27 m
Outer radius of cylinder is, r_out = 1.12×10^{-2} m
Inner radius of cylinder is, r_in = 3.9×10^{-3} m
Mass of person, m = 60 kg
Young's modulus , Y = 9.4×10^9 N/m2
(a)
Compressional strain of humerous is,



![= \frac{(60 kg)(9.8 m/s2 )}{(\pi)[( 1.12\times 10^{-2})^2 - (3.9\times 10^{-3} m)^2] (9.4\times 10^9 N/m2 )}[tex] [tex]= 1.80\times 10^{-4} m](https://tex.z-dn.net/?f=%3D%20%5Cfrac%7B%2860%20kg%29%289.8%20m%2Fs2%20%29%7D%7B%28%5Cpi%29%5B%28%201.12%5Ctimes%2010%5E%7B-2%7D%29%5E2%20-%20%283.9%5Ctimes%2010%5E%7B-3%7D%20m%29%5E2%5D%20%289.4%5Ctimes%2010%5E9%20N%2Fm2%20%29%7D%5Btex%5D%3C%2Fp%3E%3Cp%3E%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%5Btex%5D%3D%201.80%5Ctimes%2010%5E%7B-4%7D%20m)
(b) Let assume that humerous is compressed by ΔL
Since, strain = ΔL/L0

Thus,


The main component in a reflecting telescope is a mirror where the light will bounce off and is then focused into a smaller area. In contrast, a refracting telescope uses lenses that focus the light as it travels towards the other end.
Two different types of reflecting telescopes are:
1.Cassegrain reflector
2.Newtonian telescope
Explanation:
- The distinction between the two is in how they manipulate the incoming light in order to magnify the image. The main component in a reflecting telescope is a mirror where the light will bounce off and is then focused into a smaller area.
- Key advantage of reflecting telescopes is how big you can make them. With lenses, the maximum size is limited to about one meter, largely because of the problems stated above as well as the skyrocketing costs.
- The Newtonian telescope, also called the Newtonian reflector, is a type of reflecting telescope invented Sir Isaac Newton, using a concave primary mirror and a flat diagonal secondary mirror. The Newtonian telescope's simple design has made it very popular with amateur telescope makers.
- The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas, the main characteristic being that the optical path folds back onto itself, relative to the optical system's primary mirror entrance aperture.