Potential difference required in an electron microscope to give an electron wavelength of 4. 5 nm will be 0.063 V.
The difference in potential between two points that represents the work involved or the energy released in the transfer of a unit quantity of electricity from one point to the other is called potential difference.
The wavelength of an electron is calculated for a given energy (accelerating voltage) by using the de Broglie relation between the momentum p and the wavelength λ of an electron
lambda = 4.5 nm = 4.5 * 
m
h = 
J s
e = 1.6 * 
C
m = 9.1 * 
kg
Energy = eV
lambda = h / 
= h / 
= 
/ (2m (eV))
V = / (2 m e )
V = 
/ 2 * 9.1 * * 1.6 * * 
V = 0.063 V
To learn more about wavelength of an electron here
brainly.com/question/17295250
#SPJ4
Answer:
w = √[g /L (½ r²/L2 + 2/3 ) ]
When the mass of the cylinder changes if its external dimensions do not change the angular velocity DOES NOT CHANGE
Explanation:
We can simulate this system as a physical pendulum, which is a pendulum with a distributed mass, in this case the angular velocity is
w² = mg d / I
In this case, the distance d to the pivot point of half the length (L) of the cylinder, which we consider long and narrow
d = L / 2
The moment of inertia of a cylinder with respect to an axis at the end we can use the parallel axes theorem, it is approximately equal to that of a long bar plus the moment of inertia of the center of mass of the cylinder, this is tabulated
I = ¼ m r2 + ⅓ m L2
I = m (¼ r2 + ⅓ L2)
now let's use the concept of density to calculate the mass of the system
ρ = m / V
m = ρ V
the volume of a cylinder is
V = π r² L
m = ρ π r² L
let's substitute
w² = m g (L / 2) / m (¼ r² + ⅓ L²)
w² = g L / (½ r² + 2/3 L²)
L >> r
w = √[g /L (½ r²/L2 + 2/3 ) ]
When the mass of the cylinder changes if its external dimensions do not change the angular velocity DOES NOT CHANGE
Answer:
15√2 N
Explanation:
The acceleration is given by ...
a = F/m = 5t/5 = t . . . . meters/second^2
The velocity is the integral of acceleration:
v = ∫a·dt = (1/2)t^2
This will be 9 m/s when ...
9 = (1/2)t^2
t = √18 . . . . seconds
And the force at that time is ...
F = 5(√18) = 15√2 . . . . newtons
Answer:
The answer an be the option A.
Explanation:
Because radioactive substances have atomic number greater than 82.
Answer:
D a thermometer
Explanation: It measures and track Celcius and Feirinheit.
