Answer:
1, 2, 4, 5 are correct
Explanation:
1) This is true because In a neutral atom, the number of positive charges (protons) is equal to the number of negative charges (electrons).
2) This is true because the mass of the atom which is made up of the protons and neutrons, is located in the tiny nucleus.
3) This is not true because the positively charged particles in the nucleus are called protons.
4) This is true because electrons move around the nucleus in diffuse areas known as orbitals.
5) This is true because opposite charges attract each other. And electron is a negative charge.
6) This is not true because the radius of the electron cloud is normally 10,000 times larger than the radius of the nucleus.
True.
<span>Scientist use conversion factors to express the given value of a unit different type of unit</span>
Answer:
The velocity of the photo electron is
.
Explanation:
Given that,
Supplied energy, 
Minimum energy of the electron to escape from the metal, 
We need to find the velocity of the photo electron. The energy supplied by the photon is equal to the sum of minimum escape energy and the kinetic energy of the escaping electron. So,

The formula of kinetic energy is given by :

So, the velocity of the photo electron is
.
Answer:
<em>The distance covered by comet is </em>
Explanation:
Speed is defined as the rate of change of distance with time. It is given by the equation speed= 
Thus distance= 
In this problem it is given that speed of comet= 
time travelled by the comet= 4 hours
Thus distance= 
= 
= 
<span>D. density is your answer</span>