Answer:
c.
Explanation:
they are all almost correct.
c is the only fully correct option
Answer:
in first case the torque is maximum.
Explanation:
Torque is defined as the product of force and the perpendicular distance.
τ = F x d x Sinθ
In case A: the angle between force vector and the distance vector is 90 so torque is
τ = F x d
In case B: the angle between force vector and the distance is 30°.
τ = F x d x Sin30
τ = 0.5 Fd
So the torque is maximum in first case.
Answer: 
Explanation:
The kinetic energy of an electron
is given by the following equation:
(1)
Where:

is the momentum of the electron
is the mass of the electron
From (1) we can find
:
(2)
(3)
Now, in order to find the wavelength of the electron
with this given kinetic energy (hence momentum), we will use the De Broglie wavelength equation:
(4)
Where:
is the Planck constant
So, we will use the value of
found in (3) for equation (4):
(5)
We are told the wavelength of the photon
is the same as the wavelength of the electron:
(6)
Therefore we will use this wavelength to find the energy of the photon
using the following equation:
(7)
Where
is the spped of light in vacuum
Finally:
Answer:
what r the questions i can’t see them
Explanation: