Answer: because ν = velocity/λ where ν and λ are the frequency and wavelegth of the wave.
Explanation: In order to explain this problem we have to consider the relationship between frequency and wavelengths which are related by the velocity of the wave as follows ν*λ=v where ν and λ are the frequency and wavelegth of the wave. These parameters have an inverse proportionality.
Then, ν = velocity/λ
From the planks equation
E=hv
V= c/ wave length
V= 3×10^8/30×10^-9
=1×10^16
E= hv
6.63×10^-34×1×10^16
= 6.63×10^-18
A. because as the merry-go-round spins the child accelerates towards the center of the merry-go-round at a uniform rate.