Answer:
Explanation:
If Ek is the kinetic energy and m is the mass and v is the velocity then v can be calculated as follows
Ek= 1/2 ×( m × v² )
2Ek= mv²
2Ek/m = v²
v =√(2Ek/m)
m = 0.1 kg
v= √(2x8/0.1)= 12.65 m/s
Answer:
a.Attractive

Explanation:
When it comes to charges, the charges which are alike repel each other and the charges which are different will attract each other.
Here, there is a proton and electron which are different particles hence, they will attract each other.
= Charge of electron and proton = 
r = Distance between them = 997 nm
k = Coulomb constant = 
Force is given by

The force of attraction between the particles will be 
Answer:
True
Explanation:
When a ray travelling parallel to the principle axis of a concave mirror then the light ray reflect out through the mirrors and passing through the focus.
When a light ray travelling through focus of a concave mirror then after reflection the light ray reflect out through the mirror and go parallel to principle axis.
Therefore, rays travelling parallel to the principle axis of a concave mirror will reflect out through the mirrors focus.
It is true.