Answer:
material work function is 0.956 eV
Explanation:
given data
red wavelength 651 nm
green wavelength 521 nm
photo electrons = 1.50 × maximum kinetic energy
to find out
material work function
solution
we know by Einstein photo electric equation that is
for red light
h ( c / λr ) = Ф + kinetic energy
for green light
h ( c / λg ) = Ф + 1.50 × kinetic energy
now from both equation put kinetic energy from red to green
h ( c / λg ) = Ф + 1.50 × (h ( c / λr ) - Ф)
Ф =( hc / 0.50) × ( 1.50/ λr - 1/ λg)
put all value
Ф =( 6.63 ×
(3 ×
) / 0.50) × ( 1.50/ λr - 1/ λg)
Ф =( 6.63 × (3 × ) / 0.50 ) × ( 1.50/ 651×
- 1/ 521 ×)
Ф = 1.5305 ×
J × ( 1ev / 1.6 × J )
Ф = 0.956 eV
material work function is 0.956 eV
Answer:
option a.
Explanation:
We can think of an atom as a nucleus (where the protons and neutrons are) and some electrons orbiting it.
We also know that the mass of an electron is a lot smaller than the mass of a proton or the mass of an electron.
So, if all the protons and electrons of an atom are in the nucleus, we know that most of the mass of an atom is in the nucleus of that atom.
Then we define the mass number, which is the total number of protons and neutrons in an atom. Such that the mass of a proton (or a neutron) is almost equal to 1u
Then if we define A as the total number of protons and neutrons, and each one of these weights about 1u
(where u = atomic mass unit)
Then the weight of the nucleus is about A times 1u, or:
A*1u = A atomic mass units.
Then the correct option is:
The mass of the nucleus is approximately EQUAL to the mass number multiplied by __1__ Atomic Mass unit.
option a.
It has to be the last one because whenever lights are turned on it decreases because all lights are on at the same time. It's good to just have one light on. It doesn't use as much electricity.
Answer:
convection
Explanation:
Heat transfer by convection is caused by differences of temperature and density within a fluid.
This is false because an object can also be pushed by force and isn't always have to be pulled by a force.
