Find the energy of one quantum of microwave radiation with frequency 4 GHz and with 500 GHz .
1 answer:
Answer:
1. and
2.
Explanation:
The energy of a photon is given by the so-called Planck-Einstein relation:
where E is the energy, f the frequency, the wavelength, c the speed of light and h the planck constant
So, we have:
And:
2. The work function is the amount of energy required to remove an electron from the material. Therefore the kinetic energy of the photoelectrons will be the energy of the electromagnetic radiation minus the work function:
Where K is the kinetic energy and W the work function, for copper W=4.7eV
Rewriting for :
This wavelength corresponds to the ultraviolet range
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Answer:
a) v² = v₀² + 2 g h, b) t = v₀/g (1+ √ (1 + 2gh/ v₀²))
Explanation:
a) This is an exercise that we can solve using conservation of energy.
Starting point. High point
Em₀ = K + U = ½ m v₀² + m gh
Final point. Soil
= K = ½ m v²
energy is conserved because there is no friction
Emo = Em_{f}
½ m v₀² + m g h = ½ m v²
v² = v₀² + 2 g h
b) the time it takes to reach the ground can be calculated with kinematics
let's create a reference frame with positive upward direction
v = vo - g t
when it reaches the ground it has a velocity v, the initial velocity is downwards v₀ = -v₀
v = -v₀ - gt
t = - (v + v₀) / g
we substitute the velocity values calculated in the previous part
t = - (√(v₀² + 2 g h) + vo) / g
we will simplify the equation a bit
t = - v₀/g (1+ √ (1 + 2gh/ v₀²))
c) is now thrown vertically upward with the same initial velocity vo.
To find the final velocity we use the conservation of energy where the velocity is squared, so it does not matter if it is positive or negative, therefore in this section the value should be the same as in part a
v = √ (v₀² + 2gh)
d) for this part if there is change since the speed is not squared
v₀ = v₀
v = v₀ - gt
t = (v₀ - v) / g
t = (v₀ - √(v₀² + 2 g h)) / g
t = v₀/g (1 - √(1 + 2gh / v₀²))
Explanation:
Given that,
Charge acting on the object,
Force acting on the object, (in downward direction)
(a) The electric force acting in the electric field is given by :
E is the electric field
E = 4.75 N/C
The direction of electric field is as same as electric force. But it is negative charge. So, the direction of electric field is in upward direction.
(b) The charge on the proton is,
The force acting on the proton is :
If the charge on the proton is positive, the force on the proton is in upward direction.
Hence, this is the required solution.