I choose the option A.
The electron absorbs energy from specific wavelength then moving from a lower energy orbital to a higher energy orbital.
Answer:
u will equate and make V2 the subject because it's the one u are looking for ....
Answer:
Latent heat of fusion of the substance is 
Explanation:
Latent heat of fusion denotes amount of energy (heat) per unit mass required to melt a solid material at constant temperature and pressure i.e. at it's melting point
Here amount of heat required = 
Mass of unknown substance being melted = 18.5 kg
So, latent heat of fusion of the substance = (required heat energy to melt)/(mass of the unknown substance) = 
So, latent heat of fusion of the substance is 
Its of-course the inner core <span />