Answer:
λ = 4.1638 10⁻⁷ m
Explanation:
The photoelectric effect was explained by Einstein assuming that the radiation acts like particles and the equation that describes the process is
K = h f -Ф
where K is the kinetic energy of the emitted electrons, hf the energy of the photons according to Planck's equation and Ф the work function of the material
In this case they give us the kinetic energy of the electrons
K = 0.7 eV
The sodium work function is tabulated Ф = 2.28 eV
Let's find the frequency of the photons
f = (K + Ф) / h
Planck's constant is
h = 6.626 10⁻³⁴ J s (1 eV / 1.6 10⁻¹⁹ J) = 4.136 10⁻¹⁵ eV s
f = (0.7 + 2.28) / 4.136 10⁻¹⁵
f = 7.2050 10¹⁴ Hz
let's find the wavelength using the relationship between speed and frequency and wavelength
c = λ f
λ = c / f
λ = 3 10⁸ / 7.205 10¹⁴
λ = 4.1638 10⁻⁷ m
Answer : The correct option is (A) " inverse plot,
".
Explanation:
The atmospheric density is defined as the mass of the per unit volume of the atmosphere of earth. It is measured in
.
The atmospheric density on a certain planet is found to decrease as altitude increases. So, there is an inverse relationship between the density and the altitude.
From the attached graph, it is clear that there will an inverse plot for altitude vs atmospheric density.
Let point M in the graph shows 1,291 km. So, density at point M should be in between
and less than ![0.54\ kg/m^3](https://tex.z-dn.net/?f=0.54%5C%20kg%2Fm%5E3)
So, the density can be
Out of given options, the correct one must be (A) because the point M lies closer to point A.
So, correct option is (A) " inverse plot,
".
Answer:
0.00000011 m
Explanation:
n = 0 for minimum thickness
t = Thickness
= Refractive index of the film = 1.25
= Wavelength = ![550\times 10^{-9}\ m](https://tex.z-dn.net/?f=550%5Ctimes%2010%5E%7B-9%7D%5C%20m)
We have the formula
![2n_2t=(2n+1)\dfrac{\lambda}{2}](https://tex.z-dn.net/?f=2n_2t%3D%282n%2B1%29%5Cdfrac%7B%5Clambda%7D%7B2%7D)
![\\\Rightarrow t=(2n+1)\dfrac{\lambda}{4n_2}\\\Rightarrow t=(2\times 0+1)\dfrac{550\times 10^{-9}}{4\times 1.25}\\\Rightarrow t=0.00000011\ m](https://tex.z-dn.net/?f=%5C%5C%5CRightarrow%20t%3D%282n%2B1%29%5Cdfrac%7B%5Clambda%7D%7B4n_2%7D%5C%5C%5CRightarrow%20t%3D%282%5Ctimes%200%2B1%29%5Cdfrac%7B550%5Ctimes%2010%5E%7B-9%7D%7D%7B4%5Ctimes%201.25%7D%5C%5C%5CRightarrow%20t%3D0.00000011%5C%20m)
The minimum thickness of the film is 0.00000011 m
Answer:
Increase
Explanation:
because it's increasing up.