(a) The electron kinetic energy is
![K=3.00 eV](https://tex.z-dn.net/?f=K%3D3.00%20eV)
which can be converted into Joule by keeping in mind that
![1 eV=1.6 \cdot 10^{-19}eV](https://tex.z-dn.net/?f=1%20eV%3D1.6%20%5Ccdot%2010%5E%7B-19%7DeV)
So that we find
![K=3.00 eV \cdot 1.6 \cdot 10^{-19} eV/J =4.8 \cdot 10^{-19}J](https://tex.z-dn.net/?f=K%3D3.00%20eV%20%5Ccdot%201.6%20%5Ccdot%2010%5E%7B-19%7D%20eV%2FJ%20%3D4.8%20%5Ccdot%2010%5E%7B-19%7DJ)
The kinetic energy of the electron is related to its momentum p by:
![K= \frac{p^2}{2m}](https://tex.z-dn.net/?f=K%3D%20%5Cfrac%7Bp%5E2%7D%7B2m%7D%20)
where m is the electron mass. Re-arranging the equation, we find
![p= \sqrt{ 2Km}= \sqrt{ 2 ( 4.8 \cdot 10^{-19} J)(9.1 \cdot 10^{-31} kg) } =9.35 \cdot 10^{-25} kgm/s](https://tex.z-dn.net/?f=p%3D%20%5Csqrt%7B%202Km%7D%3D%20%5Csqrt%7B%202%20%20%28%204.8%20%5Ccdot%2010%5E%7B-19%7D%20J%29%289.1%20%5Ccdot%2010%5E%7B-31%7D%20kg%29%20%7D%20%3D9.35%20%5Ccdot%2010%5E%7B-25%7D%20kgm%2Fs%20)
And now we can use De Broglie's relationship to find its wavelength:
![\lambda= \frac{h}{p}= \frac{6.6 \cdot 10^{-34} Js}{9.35 \cdot 10^{-25} kg m/s} =7.06 \cdot 10^{-10}m](https://tex.z-dn.net/?f=%5Clambda%3D%20%5Cfrac%7Bh%7D%7Bp%7D%3D%20%5Cfrac%7B6.6%20%5Ccdot%2010%5E%7B-34%7D%20Js%7D%7B9.35%20%5Ccdot%2010%5E%7B-25%7D%20kg%20m%2Fs%7D%20%3D7.06%20%5Ccdot%2010%5E%7B-10%7Dm%20)
where h is the Planck constant.
(b) By using the same procedure of part (a), we can convert the photon energy into Joules:
![E=3.00 eV \cdot 1.6 \cdot 10^{-19} eV/J =4.8 \cdot 10^{-19}J](https://tex.z-dn.net/?f=E%3D3.00%20eV%20%5Ccdot%201.6%20%5Ccdot%2010%5E%7B-19%7D%20eV%2FJ%20%3D4.8%20%5Ccdot%2010%5E%7B-19%7DJ)
The energy of a photon is related to its frequency f by:
![E=hf](https://tex.z-dn.net/?f=E%3Dhf)
where h is the Planck constant. Re-arranging the equation, we find
![f= \frac{E}{h}= \frac{4.8 \cdot 10^{-19} J}{6.6 \cdot 10^{-34}Js} =7.27 \cdot 10^{14}Hz](https://tex.z-dn.net/?f=f%3D%20%5Cfrac%7BE%7D%7Bh%7D%3D%20%5Cfrac%7B4.8%20%5Ccdot%2010%5E%7B-19%7D%20J%7D%7B6.6%20%5Ccdot%2010%5E%7B-34%7DJs%7D%20%3D7.27%20%5Ccdot%2010%5E%7B14%7DHz%20%20)
And now we can use the relationship between frequency f, speed of light c and wavelength
![\lambda](https://tex.z-dn.net/?f=%5Clambda)
of a photon, to find its wavelength:
increase air resistance, which decreases gravitational acceleration
<h2>
Answer:</h2>
The photosynthesis chemical equation states that the reactants
(carbon dioxide, water and sunlight), yield two products, glucose and oxygen gas. The single chemical equation represents the overall process of photosynthesis.
hope this help you!
The answer for this question would be choice "<span>B. The average annual dose of background radiation is 250 times smaller than the dose linked to increased cancer risk."
You only have to compare 4.0 x 10^-4 and 1.0 x 10^-1. And if you can observe carefully, when you try to multiply the average annual dose of background radiation by 250, you would get 0.1 which is equivalent to the amount of annual dose linked to increased cancer risk. Therefore, the answer is B.</span>
Answer:
<h2>50
°</h2>
Explanation:
Angle of rotation of the flat polished surface
= 15°
angle of incidence i = 20°
Since the polished surface is turned at an angle of 15°, the angle of reflection
r = 2
(Note that the angle of rotation only have effect of the angle of reflection)
r = 2*15 = 30°
The angle between the reflected ray and the incident ray will be equal to the sum of the angle of incidence and the angle of reflection i.e i+r
The angle between the reflected ray and the incident ray = 20°+ 30° = 50°