Angles are generally measured counter clockwise from positive x- axis. suppose you have a vector lying in the x-y plane. when you determined its direction using vector method, you got the angle as negative. what does that indicate? both the components of the vector must be negative (lying in the 3rd quadrant). the vector must be lying in the 4th quadrant. 2 at least one of the components of the vector 3 is negative. the vector must be lying in the first quadrant. 4 it is not possible to have a negative angle for a vector. 5 exactly one of the components is negative.

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.

c. magnitude and direction

answer: a. same unit

explanation:

the components of a vector are the parts of the vectors that are to each other.

b perpendicular