Change in position of object = Displacment
Answer:
![v = 4.44 \times 10^5 m/s](https://tex.z-dn.net/?f=v%20%3D%204.44%20%5Ctimes%2010%5E5%20m%2Fs)
Explanation:
By Einstein's Equation of photoelectric effect we know that
![h\nu = W + \frac{1}{2}mv^2](https://tex.z-dn.net/?f=h%5Cnu%20%3D%20W%20%2B%20%5Cfrac%7B1%7D%7B2%7Dmv%5E2)
here we know that
= energy of the photons incident on the metal
= minimum energy required to remove photons from metal
= kinetic energy of the electrons ejected out of the plate
now we know that it requires 351 nm wavelength of photons to just eject out the electrons
so we can say
![W = \frac{hc}{351 nm}](https://tex.z-dn.net/?f=W%20%3D%20%5Cfrac%7Bhc%7D%7B351%20nm%7D)
here we know that
![hc = 1242 eV-nm](https://tex.z-dn.net/?f=hc%20%3D%201242%20eV-nm)
now we have
![W = \frac{1242}{351} = 3.54 eV](https://tex.z-dn.net/?f=W%20%3D%20%5Cfrac%7B1242%7D%7B351%7D%20%3D%203.54%20eV)
now by energy equation above when photon of 303 nm incident on the surface
![\frac{1242 eV-nm}{303 nm} = 3.54 eV + \frac{1}{2}(9.1 \times 10^{-31})v^2](https://tex.z-dn.net/?f=%5Cfrac%7B1242%20eV-nm%7D%7B303%20nm%7D%20%3D%203.54%20eV%20%2B%20%5Cfrac%7B1%7D%7B2%7D%289.1%20%5Ctimes%2010%5E%7B-31%7D%29v%5E2)
![4.1 eV = 3.54 eV + (4.55 \times 10^{-31}) v^2](https://tex.z-dn.net/?f=4.1%20eV%20%3D%203.54%20eV%20%2B%20%284.55%20%5Ctimes%2010%5E%7B-31%7D%29%20v%5E2)
![(4.1 - 3.54)\times 1.6 \times 10^{-19}) = (4.55 \times 10^{-31}) v^2](https://tex.z-dn.net/?f=%284.1%20-%203.54%29%5Ctimes%201.6%20%5Ctimes%2010%5E%7B-19%7D%29%20%3D%20%284.55%20%5Ctimes%2010%5E%7B-31%7D%29%20v%5E2)
![8.96 \times 10^{-20} = (4.55 \times 10^{-31}) v^2](https://tex.z-dn.net/?f=8.96%20%5Ctimes%2010%5E%7B-20%7D%20%3D%20%284.55%20%5Ctimes%2010%5E%7B-31%7D%29%20v%5E2)
![v = 4.44 \times 10^5 m/s](https://tex.z-dn.net/?f=v%20%3D%204.44%20%5Ctimes%2010%5E5%20m%2Fs)
To find speed you have to divide distance by time. In this case:
5 meters➗3 seconds = about 1.66666666 and so on m/s.
You could round to 1.67 or 1.7 if you'd like.
Answer:
Explanation:
If the object is falling straight down it is in free fall. The difference between that and two-dimensional motion is that 2D motion is parabolic (projectile)
Answer:
The speed of the electron is 1.371 x 10⁶ m/s.
Explanation:
Given;
wavelength of the ultraviolet light beam, λ = 130 nm = 130 x 10⁻⁹ m
the work function of the molybdenum surface, W₀ = 4.2 eV = 6.728 x 10⁻¹⁹ J
The energy of the incident light is given by;
E = hf
where;
h is Planck's constant = 6.626 x 10⁻³⁴ J/s
f = c / λ
![E = \frac{hc}{\lambda} \\\\E = \frac{6.626*10^{-34} *3*10^{8}}{130*10^{-9}} \\\\E = 15.291*10^{-19} \ J](https://tex.z-dn.net/?f=E%20%3D%20%5Cfrac%7Bhc%7D%7B%5Clambda%7D%20%5C%5C%5C%5CE%20%3D%20%5Cfrac%7B6.626%2A10%5E%7B-34%7D%20%2A3%2A10%5E%7B8%7D%7D%7B130%2A10%5E%7B-9%7D%7D%20%5C%5C%5C%5CE%20%3D%2015.291%2A10%5E%7B-19%7D%20%5C%20J)
Photo electric effect equation is given by;
E = W₀ + K.E
Where;
K.E is the kinetic energy of the emitted electron
K.E = E - W₀
K.E = 15.291 x 10⁻¹⁹ J - 6.728 x 10⁻¹⁹ J
K.E = 8.563 x 10⁻¹⁹ J
Kinetic energy of the emitted electron is given by;
K.E = ¹/₂mv²
where;
m is mass of the electron = 9.11 x 10⁻³¹ kg
v is the speed of the electron
![v = \sqrt{\frac{2K.E}{m} } \\\\v = \sqrt{\frac{2*8.563*10^{-19}}{9.11*10^{-31}}}\\\\v = 1.371 *10^{6} \ m/s](https://tex.z-dn.net/?f=v%20%3D%20%5Csqrt%7B%5Cfrac%7B2K.E%7D%7Bm%7D%20%7D%20%5C%5C%5C%5Cv%20%3D%20%20%5Csqrt%7B%5Cfrac%7B2%2A8.563%2A10%5E%7B-19%7D%7D%7B9.11%2A10%5E%7B-31%7D%7D%7D%5C%5C%5C%5Cv%20%3D%201.371%20%2A10%5E%7B6%7D%20%5C%20m%2Fs)
Therefore, the speed of the electron is 1.371 x 10⁶ m/s.