It regulates the amount of light passing through the spicemen. A. arm B. base C. body tube D. diaphragm

D. diaphragm

Explanation:

The question above is related to the different parts of the microscope. Among the choices above, it is the diaphragm that regulates the amount of light passing through the specimen. This is located below the stage (the platform where the slide of specimen is placed). With the help of the diaphragm, the intensity of light is controlled, which allows the observer to see the specimen in the best contrast.

Additional Information:

The arm links the base of the microscope to its head.

The base simply supports the microscope.

The body tube links the objective lenses to the eyepiece.

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.

when it gains or loses electrons