Question

Black holes have such a strong gravity that escape velocity from it is more than speed of light which basically means nothing could escape it.

Everything in the universe have escape velocity. For Earth it is 11.2 km/s which means if any body has speed of 11.2 km/s from earth's surface then it could reach infinite distance away and would never come back to earth.

If something has half the speed of escape velocity say 5.6 km/s then the body would return back to earth after travelling some distance.

Suppose a black hole have escape velocity double the speed of light the it would mean photons can't escape it.

But as in our previous example of earth where body with 5.6 km/s speed travelled some distance before coming back to earth in the same way any photon emitted from that black hole would travel some distance before coming back to black hole.

It would mean if any person is standing outside the range of that photon he wouldn't see black hole but he could see it if he go close in range of the photon.

A very similar question could be that if any photon is emitted from the surface of earth then would its speed decrease or energy decrease as it move away like blue light photon turn less intense .
Options:
A) The speed of the photon decreases gradually as it moves away from Earth's surface.
B) The energy of the photon decreases as it moves away from Earth's surface.
C) Neither the speed nor the energy of the photon decreases as it moves away from Earth's surface.
D) The speed and energy of the photon both increase as it moves away from Earth's surface.

Answer 1

Black holes have such strong gravity that their escape velocity is greater than the speed of light, making it impossible for anything, including light, to escape them. If a photon is emitted from the surface of a black hole, it would not be able to escape and would eventually fall back into the black hole. On Earth, if an object has a speed less than the escape velocity, it will return back to Earth. The correct answer is C) Neither the speed nor the energy of the photon decreases as it moves away from Earth's surface.

Step-by-step explanation:

Black holes have such strong gravity that their escape velocity is greater than the speed of light, which means that nothing can escape them, including light itself.

For example, if a photon is emitted from the surface of a black hole, it would not be able to escape and would eventually fall back into the black hole.

In the case of Earth, its escape velocity is 11.2 km/s. If an object has a speed greater than or equal to this value, it can escape Earth's gravity and travel to infinite distances.

However, if an object has a speed less than the escape velocity, like 5.6 km/s, it would eventually return back to Earth.

Regarding the question about photons emitted from the surface of Earth, neither the speed nor the energy of the photon decreases as it moves away.

The speed of light is constant and does not change with distance.

However, the intensity or brightness of light can decrease due to factors such as absorption and scattering.

Therefore, the correct answer is C) Neither the speed nor the energy of the photon decreases as it moves away from Earth's surface.