After a nucleus with 85 protons undergoes alpha decay, it has ? protons.
1 answer:
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Answer:
The near point of an eye with power of +2 dopters, u' = - 50 cm
Given:
Power of a contact lens, P = +2.0 diopters
Solution:
To calculate the near point, we need to find the focal length of the lens which is given by:
Power, P =
where
f = focal length
Thus
f =
f = = + 0.5 m
The near point of the eye is the point distant such that the image formed at this point can be seen clearly by the eye.
Now, by using lens maker formula:
where
u = object distance = 25 cm = 0.25 m = near point of a normal eye
u' = image distance
Now,
Solving the above eqn, we get:
u' = - 0.5 m = - 50 cm
The De Broglie wavelength of the electron is
And we can use De Broglie's relationship to find its momentum:
Given
, with m being the electron mass and v its velocity, we can find the electron's velocity:
This velocity is quite small compared to the speed of light, so the electron is non-relativistic and we can find its kinetic energy by using the non-relativistic formula:
And we can use De Broglie's relationship to find its momentum:
Given
This velocity is quite small compared to the speed of light, so the electron is non-relativistic and we can find its kinetic energy by using the non-relativistic formula: