Which of the following particle has similar mass to electron

The nuclear radius is given by $R=r_0 A^{1 / 3}$, where $r_0$ is constant and $A$ is the atomic mass number. Then, the nuclear mass density of $U^{238}$ is

Give a general introduction to the nucleus. 

Assertion : Neutrons penetrate mater more readily as compared to protons.

Reason : Neutrons are slightly more massive than protons.

Assume that the nuclear binding energy per nucleon $(B/A)$ versus mass number $(A)$ is as shown in the figure. Use this plot to choose the correct choice $(s)$ given below

$(A)$ Fusion of two nuclei with mass numbers lying in the range of $1 < A < 50$ will release energy

$(B)$ Fusion of two nuclei with mass numbers lying in the range of $51 < A < 100$ will release energy

$(C)$ Fission of a nucleus lying in the mass range of $100 < A < 200$ will release energy when broken into two equal fragments

$(D)$ Fission of a nucleus lying in the mass range of $200 < A < 260$ will release energy when broken into two equal fragments

Is nuclear force short range or long range ?