You have three known variables:
Acceleration -

Time -

Initial Velocity -

For the first part of your question:

For the second part of your question:

This still needs to be converted to m/h:
Answer:
Explanation:
If the energy levels of n1 and n2 are high, the difference of their energy level will tend to zero thereby making the energy of the emitted photons very low.
Answer:
1. 1, 2, 4 all show some form of refraction as the bending of a light ray when passing from one media to another.
Explanation:
Number 4 is the most accurate as it also shows some light being reflected and the bending of the refracted light ray in the correct direction for going from a medium of low refractive index (air) into a higher refractive index material (crown glass)
Not at all. Density on its own is not sufficient
Answer: a switch can do A, B and E
Explanation: