Which nuclear phenomenon produces a change in the mass number of a nucleus? 1. alpha decay 2. electron capture 3. gamma ray emission 4. positron emission

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.

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .

with this one i know the answer in craters one reason i looked it up and i learned about it there is my evidence