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
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Answer:
Quantum theory
Explanation:
The scientific foundation in quantum mechanics is quantum theory, which describes the existence and behavior of mass and antimatter at the subatomic particles levels. Quantum theory and quantum theory are often related to as the existence and behavior of matter in the universe at that stage.
11/23/2012 - 2.2 mag, 5.0mi depth 1.0875 mi from <span>Gloucester Township, NJ
</span>
<u>Answers
</u>
1) B. longitudinal.
2) B. air is cooler than the ground.
<u>Explanation
</u>
Q1
There are two categories of a wave. That is transverse and longitudinal waves. Transverse waves forms crests and troughs while longitudinal forms compressions and rarefaction as they travel. Rarefactions are regions where the wavelengths are longer than other regions.
Q2
As the ray of light moves from an optically less dense to a more dense region it bends towards the normal.
If the sound is bending away from the earth's surface, then the ground must be warmer than the air. As the sound travels it moves from optically dense medium to a less dense medium. For this reason it bends away from the normal. This can only happen when, B. air is cooler than the ground.