The power of the antenna is

and since the power is the emitted energy divided by the time, the energy emitted per second is

The frequency of the emitted photons is

So the energy of a single photon is

Therefore, to find the number of emitted photons per second, we should divide the total energy emitted by the antenna in 1 second by the energy of a single photon:
Answer:
Condition

Explanation:
Basically black hole is an object from which light rays can not escape it means to go out from gravitational field , that body should thrown with speed greater then light.
Let's do some calculation
Gravitational potential at surface =
If we give kinetic energy equal to magnitude of Potential energy as on surface it will escape.
=
⇒
It will be more better for black hole if above ratio (analogous to density ) is more then above calculated
Answer:
The answer is in 3 point
Choose which point you like
Answer:
Add the two speeds together.
Then, divide the sum by two. This will give you the average speed for the entire trip. So, if Ben traveled 40 mph for 2 hours, then 60 mph for another 2 hours, his average speed is 50 mph.