The magnetic force on a charged moving particle: a) depends on the sign of the charge on the particle. b) depends on the magnetic field at the particle's instantaneous position. c) is described by all of these statements. d) is proportional both to the charge and to the magnitude of the magnetic field. e) is in the direction which is mutually perpendicular to the direction of motion of the charge and the direction of the magnetic field.

All of the statements are correct

Explanation:

Hello!

All of the statements are rigth. You can know this by examining the Lorentz Force:

a )

The dependence on the charge sign can be inferrend by the term q which is the particle's charge. If it changes sign, the force also does.

b)

Although we usually deal with constant magntic Fields, they could also be position dependent, for example the magnetic field of a wire. The fild of teh force will also inherit this position dependence, that is:

c)

d)

Again, from  the equation of the force or Lorentz force, we can see that this statement is true.

d)

The validity of this statement is given by the cross product between the velocity (which points twoards the direction of motion of the particle) and the magnetic field

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.