A) We want to find the work function of the potassium. Apply this equation:
E = 1243/λ - Φ
E = energy of photoelectron, λ = incoming light wavelength, Φ = potassium work function
Given values:
E = 2.93eV, λ = 240nm
Plug in and solve for Φ:
2.93 = 1243/240 - Φ
Φ = 2.25eV
B) We want to find the threshold wavelength, i.e. find the wavelength such that the energy E of the photoelectrons is 0eV. Plug in E = 0eV and Φ = 2.25eV and solve for the threshold wavelength λ:
E = 1243/λ - Φ
0 = 1243/λ - Φ
0 = 1243/λ - 2.25
λ = 552nm
C) We want to find the frequency associated with the threshold wavelength. Apply this equation:
c = fλ
c = speed of light in a vacuum, f = frequency, λ = wavelength
Given values:
c = 3×10⁸m/s, λ = 5.52×10⁻⁷m
Plug in and solve for f:
3×10⁸ = f(5.52×10⁻⁷)
f = 5.43×10¹⁴Hz
You need to know everything is made of atoms they are always colliding and they are never still because you'd think that every thing in space is still all the time even if it's not making visibly
Answer:
(a) 294 J
(b) 229591.84 kg
Explanation:
height, h = 30 m
g = 9.8 m/s^2
(a) U = m x g x h
U = 1 x 9.8 x 30
U = 294 J
(b) Let the mass of water is m
U = m x g xh
80% of this energy per second is generating power
0.8 x m x 9.8 x 30 = 54 x 10^6
m = 229591.84 kg
Thus, the mass of water required is 229591.84 kg.
Answer:
<em>The answer is C.</em>
Explanation:
Cells are the smallest organisms and makes up all living thing or being. The tissues are made of cells. The organs are made of tissues. The organ systems are made of organs. Therefore the order is C. cells, tissues, organs, and organ systems.
