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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Gravity causes falling objects to accelerate.
Answer:
Explanation:
Sun's dynamo means the process that produce Sun's magnetic field.
The mechanism inside a Sun acts like a generator that produces electric current and magnetic field.
Magnetic field with in the Sun are extended out and around. Magnetic field of lines get twisted due to rotation of Sun.
The material that flows inside the Sun plays an important role in Sun's dynamo. At surface the flow rate is about 20 m/s but as it moves towards equator, it becomes way too slow taking about 11 years of time.
Due to the this magnetic field, several sun spots are formed on the surface.
The number of sunspots keep on changing from minimum to maximum number resulting into change in the magnetic pole. In each cycle polarity get reversed hence the overall magnetic cycle has an interval of 22 years.
Answer:
Weight is a consequence of the universal law of gravitation
Explanation:
Weight, gravitational force of attraction on an object, caused by the presence of a massive second object, such as the Earth or Moon. Weight is a consequence of the universal law of gravitation: any two objects, because of their masses, attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.