Answer: 
Explanation:
The energy 
of a photon is given by:
(1)
Where:
is the Planck constant
is the frequency light
On the other hand, there is an inverse relationship between and the wavelength 
:
(2)
Where:
is the speed of light
is the wavelength
Substituting (2) in (1):
(3)
Finally:
This is the energy of a photon of blue light, in Joules.
The bar magnet and the electromagnet act identical. The difference being a electromagnet is a coil of wire that has a power source connect to both ends, this energizes the coil with an electromagnetic field.
Answer: A
Explanation:
Isotopes of different elements differ by the number of neutrons inside the nucleus.
