A neutron star consists of neutrons at approximately nuclear density. Estimate, for a 10-km-diameter neutron star its mass number, its mass, the acceleration of gravity at its surface.

a) 7.2*10^55

b) 1.2*10^29 kg

c) 3.2*10^11 m/s

Explanation:

Given a diameter of 10 km, that's a radius of 5 km.

We first attempt to find its mass number

A = (r/1.2*10^-15)³

A = (5/1.5*10^-15)³

A = 7.2*10^55

This gotten mass number is then multiplied by the mass of each neutron in the star. With each neutron being, 1.7*10^-27

M = 7.5*10^55 * 1.7*10^-27

M = 1.2*10^29 kg

And finally, using the formula

g = GM/r², we can find its acceleration due to gravity.

g = (6.67*10^-11 * 1.2*10^29) / 5000²

g = 8*10^18 / 2.5*10^7

g = 3.2*10^11 m/s

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.

where is the photo and the answer choices?