Answer:
A) & B)
Explanation:
First, the numbers 12 and 13 represent the <em>atomic mass number</em> of the atoms.
- So, A) is true: thus Carbon12 and Carbon 13 have different mass numbers.
The <em>mass number</em> is equal to the total number of protons and neutrons. Consider that any element has the same number of protons, regardless of the number of neutrons. The number of protons in Carbon is 6.
The amount of neutrons can be calculated by: <em>mass number </em>minus <em>number of protons.</em>
For Carbon 12: 
For Carbon 13: 
- B) is true, we just proved they have different amounts of neutrons.
In order for the charge of the atom to be neutral, the amount of electrons must be equal to the number of protons (as they have opposite charges). And we now know that the number of protons in Carbon12 and Carbon13 are always the same
- C) is false, the number of electrons is the same in both atoms
The atomic charges in both are neutral, due to the fact that they have the same amount of protons and electrons in both cases. Is only the neutrons (thus the mass numbers)that change
- D) is false, they have equal atomic charges
Answer:
A
Explanation:
The magnet can always attract other things.
Answer:

Explanation:
Given that,
Radius of a spherical shell, r = 0.7 m
Torque acting on the shell, 
Angular acceleration of the shell, 
We need to find the rotational inertia of the shell about the axis of rotation. The relation between the torque and the angular acceleration is given by :

I is the rotational inertia of the shell

So, the rotational inertia of the shell is
.
The total quantity of electrons that have flowed through a circuit is a
quantity of charge, measured in Coulombs, or in Ampere-seconds.
The <em><u>rate</u></em> of flow of electrons, or more accurately the rate of flow of
the charge on them, is electrical current. Its unit is the Ampere.
1 Ampere is 1 Coulomb of charge per second.