You are standing on the beach counting waves. you use the pier to estimate that there is 5 m between wave crests and you measure that a wave takes 2 seconds to pass your location. what is the speed of the wave?

2.5 m/s

Explanation:

In this problem, we know:

is the wavelength of the wave (distance between two successive crests)

is the period of the wave (the time it takes a wave to pass the location)

From the period, we can find the frequency of the wave:

And now we can find the speed of the wave by using the following equation:

b

explanation:

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.