Does every black hole have its mass within its Schwarzschild radius, where the mass of the black hole is the one inside its event horizon? I know that the converse is correct: every object whose mass is compressed under its Schwarzschild radius will become a black hole. But is this a necessary co...

I have a vector $F_e$ and I would like to graph it to its corresponding $X$ and $Y$ components. I know that the $i_y$ component is negative, and there is no $i_x$ component. $\vec{F_e} = F_x\vec{i_x} + F_y\vec{i_y}$ $\vec{F_e} = F_y\vec{(-i_y)}$ And to get there we have: $F_{ex}=|\vec{F_{ex}}|\co...

We know, a body in uniform linear motion will continue to move with uniform velocity unless any external force acts on it. Similarly, a body rotating with uniform angular velocity will continue to rotate with uniform angular velocity unless any external torque acts on it. Occupants inside a body ...

It's often thought the force between to charges is given by $F = \frac{q\,Q}{4\,\pi\varepsilon_0}\,\frac{1}{r^2}$, because observations lead to this. On the other side I've barely heard about how it's consistent with reality. In fact, I've never heard a professor say it's not valid for tiny dista...

I found that in every book (till my 12th) it is written that, in concave mirror, when object is at focus, then reflected rays will be parallel and they meet at infinity to form a real image. But, as we know, parallel rays never meet. Then, does this mean that all books are wrong ? If not, then why?

As we know that an electric current is a flow of electric charge in a circuit, and in electric circuits, the charge carriers are often electrons moving through a wire. Now, since we know that like charges repel each other, then how do the electrons flow through a wire since they are like charges ...