Black hole
hope it helped
Answer:

Explanation:
The Planck Eistein relation, states that the energy of a photon is proportional to its frequency:

h is the Plank constant.The frequency of a photon is defined as the speed of light over its wavelength:

Replacing (2) in (1):

Answer:
(B) tightly packed protons and neutrons
Explanation:
- Nucleus of any atom is the dense central part of any atom.
- It consists of two sub-atomic particle namely proton and neutron.
- These sub-atomic parts are tightly packed in nucleus which makes the nucleus dense .
- This dense nucleus is responsible for most of the mass of atom.
- The atomic mass for any atom is decided by sum of the mass of proton and neutron
Thus, correct answer is
(B) tightly packed protons and neutrons
Answer:
2.35 seconds
Explanation:
Remark
This is a question where direction matters. Let us call down + and up minus. It won't matter. The answer will be the same.
Formula
a = (vf - vi)/t
Givens
a = 9.8 m/s^2
vi = - 15 m/s
vf = 8m/s
Solution
9.8 = (8 - - 15)/t Multiply both sides by t
t * 9.8 = 23 Divide by 9.8
t = 23/9.8
t = 2.35 s