Which of the following could be possible vector directionsa. northb. southc. westd. 45 degrees north of east

A vector in a given plane can have any direction

In XY plane we can say that its direction is

North = + Y direction

South = - Y direction

East = + X direction

West = - X direction

so all of the above directions can be considered as direction of a given vector as a vector can incline in all above direction as well and at any angle with all also

so here it is also possible to have a direction which is along 45 degree North of East which will incline between X and Y direction both

So here all four options may be the possible direction of a vector

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.