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.
Answer: a) 127 eV; b) there is no change of kinetic energy.
Explanation: In order to explain this problem we have to use the change of potentail energy ( conservative field) is equal to changes in kinetic energy. So for the proton ther move to lower potential then they gain kinetic energy from the electric field. This means the electric force do work in this trayectory and then the protons increased changes its speed.
If we replace the proton by a electron we have a very different situaction, the electrons are located in a lower potental then they can not move to higher potential if any external force does work on the system.
In resumem, the electrons do not move from a point with V=87 to other point with V=-40 V. The electric force point to high potential so the electrons can not move to lower potential region (V=-40V).
Answer:
1.122 m/s
Explanation:
So usually a river with a speed of 1 meters per second can transport particle that weighs:
If the particle is twice as massive as usual, then its weights would be 1 * 2 = 2kg
This means the river must be flowing at a speed of
Answer:
D. The tea loses heat to the spoon causing the spoon to become warmer
Explanation:
When the silver spoon at a lower temperature than the tea, is added to the tea, it makes thermal contact. Hence, the heat transfer starts between the two until the equilibrium is reached. We know that the heat transfer takes place from the body with a higher temperature to a body with a lower temperature. As a result, the body with higher temperature loses heat and its temperature lowers down. While the body with a lower temperature gains heat and its temperature rises.
Therefore, the correct option is:
<u>D. The tea loses heat to the spoon causing the spoon to become warmer</u>
