A compound is the substances that are formed by combining two are more chemical elements. A mixture is a substance created from two or more matter that can be separate with the help of physical methods. ... Mainly pure water is part of the compound. Mixtures fall under impure water.
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Answer:
True The net force must be zero for the acceleration to be zero
Explanation:
In order to analyze the statements of this problem we propose your solution.
First let's look at Newton's first, which stable that every object is at rest or with constant speed unless something takes it out of this state (acceleration)
Now let's look at the second postulate, which says that force is related to the product of the mass of a body and its acceleration.
As a result of these two laws, for a body is a constant velocity the summation force on it must be zero.
Now we can analyze the statements given.
True The net force must be zero for the acceleration to be zero
False. If the force is different from zero, there is acceleration that changes the speeds
False. There may be forces, but the sum of them must be zero
False. If a force acts, the acceleration is different from zero and the speed changes
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
