C. Three isotopes of the same element because the number of electrons and protons remain the same but the number of neutrons in the nucleus are different. This means that the isotopes have different masses to each other but the same chemical properties.
Well the heat that is needed to raise the temperature of 10g of water by 17oC is 7
The electric force acting on the charge is given by the charge multiplied by the electric field intensity:

where in our problem

and

, so the force is

The initial kinetic energy of the particle is zero (because it is at rest), so its final kinetic energy corresponds to the work done by the electric force for a distance of x=4 m:
Answer:

Explanation:
The charge on one object, 
The distance between the charges, r = 0.22 m
The force between the charges, F = 4,550 N
Let q₂ is the charge on the other sphere. The electrostatic force between two charges is given by the formula as follows :

So, the charge on the other sphere is
.
Answer:
Yes , it is possible for two different atoms of carbon to have different numbers of neutrons in their nuclei .
Explanation:
Isotopes -
Atoms of the element with same number of the electrons and protons , but differ in the number of neutrons , are called as the isotopes .
The isotopes of the element have the same number of protons and electrons , hence have the same chemical and physical properties .
Many isotopes occurs naturally .
In case of Carbon ,
Carbon too have isotopes ,
i.e.
Carbon - 13 and Carbon - 14
carbon - 13 , have seven neutrons
Carbon - 14 , have eight neutrons .