Answer:
![5.04\cdot 10^8 A](https://tex.z-dn.net/?f=5.04%5Ccdot%2010%5E8%20A)
Explanation:
The work function of the metal corresponds to the minimum energy needed to extract a photoelectron from the metal. In this case, it is:
![\phi = 3.950\cdot 10^{-19}J](https://tex.z-dn.net/?f=%5Cphi%20%3D%203.950%5Ccdot%2010%5E%7B-19%7DJ)
So, the energy of the incoming photon hitting on the metal must be at least equal to this value.
The energy of a photon is given by
![E=\frac{hc}{\lambda}](https://tex.z-dn.net/?f=E%3D%5Cfrac%7Bhc%7D%7B%5Clambda%7D)
where
h is the Planck's constant
c is the speed of light
is the wavelength of the photon
Using
and solving for
, we find the maximum wavelength of the radiation that will eject electrons from the metal:
![\lambda=\frac{hc}{E}=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{3.950\cdot 10^{-19} J}=5.04\cdot 10^{-7}m](https://tex.z-dn.net/?f=%5Clambda%3D%5Cfrac%7Bhc%7D%7BE%7D%3D%5Cfrac%7B%286.63%5Ccdot%2010%5E%7B-34%7D%20Js%29%283%5Ccdot%2010%5E8%20m%2Fs%29%7D%7B3.950%5Ccdot%2010%5E%7B-19%7D%20J%7D%3D5.04%5Ccdot%2010%5E%7B-7%7Dm)
And since
1 angstrom = ![10^{-15}m](https://tex.z-dn.net/?f=10%5E%7B-15%7Dm)
The wavelength in angstroms is
![\lambda=\frac{5.04\cdot 10^{-7} m}{10^{-15} m/A}=5.04\cdot 10^8 A](https://tex.z-dn.net/?f=%5Clambda%3D%5Cfrac%7B5.04%5Ccdot%2010%5E%7B-7%7D%20m%7D%7B10%5E%7B-15%7D%20m%2FA%7D%3D5.04%5Ccdot%2010%5E8%20A)
Answer:
e. All of these statements are false.
Explanation:
As we know that heat transfer take place from high temperature to low temperature.
It is possible to convert all work into heat but it is not possible to convert all heat in to work some heat will be reject to the surrounding.
The first law of thermodynamics is the energy conservation law.
Second law of thermodynamics states that it is impossible to construct a device which convert all energy into work without rejecting the heat to the surrounding.
By using heat pump ,heat can transfer from cooler body to the hotter body.
Therefore all the answer is False.
The answer is true...............
Answer:
It should be fibre optic cable , buried underground
Fusion reactions happen in stars