Answer:
if this surface has a higher index than in the medium where the light travels, the reflected wave has a phase change of 180º
Explanation:
When a ray of light falls on a surface if this surface has a higher index than in the medium where the light travels, the reflected wave has a phase change of 180º this can be explained by Newton's third law, the light when arriving pushes the atoms of the medium that is more dense, and these atoms respond with a force of equal magnitude, but in the opposite direction.
When the fractional index is lower than that of the medium where the reflacted beam travels, notice a change in phase.
Also, when light penetrates the medium, it modifies its wavelength
λ = λ₀ / n
We take these two aspects into account, the condition for contributory interference is
d sin θ = (m + 1/2) λ
for destructive interference we have
d sin θ = m λ
in general this phenomenon is observed at 90º
2 d = (m +1/2) λ° / n
2nd = (m + ½) λ₀
Radiation emitted by a body is a consequence of thermal agitation of its composing molecules. so...<span> electromagnetic waves ?</span>
Answer: A. Work is done on the system and heat is transferred from the system for a net decrease in internal energy.
Explanation:
A refrigerator is a device which dispenses heat from the close system to a warmer area or in the surrounding. By dispensing the heat the internal temperature of the refrigerator drops. The system of refrigerator violates the second law of thermodynamics. As it performs the work to cool the region instead of heating the region. The work is done on the system and the internal energy decreases and the heat energy is liberated to the surrounding area. A refrigerator is an open system.
Given data
*The given mass of the pendulum is m = 3 kg
*The given height is h = 0.3 m
The formula for the maximum speed of the pendulum is given as
![v_{\max }=\sqrt[]{2gh}](https://tex.z-dn.net/?f=v_%7B%5Cmax%20%7D%3D%5Csqrt%5B%5D%7B2gh%7D)
*Here g is the acceleration due to the gravity
Substitute the values in the above expression as
![\begin{gathered} v_{\max }=\sqrt[]{2\times9.8\times0.3} \\ =2.42\text{ m/s} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20v_%7B%5Cmax%20%7D%3D%5Csqrt%5B%5D%7B2%5Ctimes9.8%5Ctimes0.3%7D%20%5C%5C%20%3D2.42%5Ctext%7B%20m%2Fs%7D%20%5Cend%7Bgathered%7D)
Hence, the maximum speed of the pendulum is 2.42 m/s
Answer:
D. the same as force. the applied force per cross-sectional area.
Explanation:
Tensile stress of a material is defined as the ratio of the applied force on the material to its cross sectional area. this is expressed mathematically as;
Tensile stress = Force/cross sectional area
Tensile stress = F/A
Force is measured in newton while cross sectional area is measured in m
Hence the unit of Tensile stress is N/m²
