the answer is definitely A.
The correct answer is B because isotopes have different numbers of neutrons, and neutrons are located in the nucleus
Hope this helps
1) Assuming an adult person has an average mass of m=80 kg, and assuming it takes about 30 seconds to climb 5 meters of stairs, the energy used by the person is

So the power output is

And since the estimate we made is very rough, we can say that the power output of the person is comparable to the power output of the light bulb of 100 W.
2) Based on the results we found in the previous part of the exercise, since the power output of the person is comparable to the power output of 1 light bulb of 100 W, we can say that the person could have kept burning only one 100-W light bulb during the climb.
Explanation:
This should be of help:
An atom is made up of three subatomic particles:
- Protons are the positively charged particles.
- Electrons are the negatively charged particles.
- Neutrons do not carry any charges.
A neutral atom is an atom that has not lost or gained any amount of electrons.
In a neutral atom;
the number of protons and electrons are the same
Usually atoms are designated this way:
ᵃₙX
where X is the symbol of the atom
a is the mass number of the atom
n is the atomic number of the atom
The mass number = number of protons + number of neutrons
Atomic number = number of protons
Note; atomic number is the same as the number protons and the number of electrons in a neutral atom.
Use this guide to solve the problem
Learn more:
Atomic number brainly.com/question/5425825
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