Answer:
A. elements of the same kind with different numbers of neutrons
Explanation:
As we know that an atom is represented by

here we know that
z = atomic number
A = atomic number + number of neutrons
now if the number of neutrons in an atom is different but having same number atomic number then the combination of such group of atoms is known as isotopes.
So here we have

so above is the example of isotopes
Answer:
Explanation:
Input refers to the amount of energy put into a device, and output refers to the amount of energy that comes out. A device may change the type of energy but not the amount. For example, a light bulb's input energy is the form of electrical energy, and its output energy is in the form of light and heat. Efficiency.
100m ÷ 50s = 2m/s
Just some simple divison.
I think the correct answer from the choices listed above is option B. It is the electrons that flow because of electrical attraction and repulsion causes an electric current in a wire. Electrons, which continuously move in wire, are called Electric Current. Hope this answers the question.
B 20 m/s
It should go to 100 that fast nor 40