Energy of gamma rays is given by equation

here we know that
h = Planck's constant

now energy is given as


now by above equation



now for wavelength we can say



D. F=ma
F is for force, and that equals two things, M for mass and A for acceleration. When mass is accelerated, it gives you force. Force equals multiplying mass and its acceleration.
According to the statements the number of electrons is 150, then
e = 150
But there is a positive charge of +22e, then the number of protons would be
p = 150+172
If the mass of the electrons is

And the mass of the protong is

We have that the total mass of the system would be



Average acceleration: velocity/time
5/4= 1.25 m/s² Acceleration
Hope I helped :)