Explanation:
Given parameters:
Wavelength of photon = 1.95 x 10⁻¹¹m
Unknown:
Frequency of the wave = ?
Energy of the photon = ?
Solution:
The frequency and wavelength of a wave are related by the expression;
C = Fλ
C = speed of light = 3 x 10⁸m/s
F = frequency
λ = wavelength
Insert the parameters and solve;
3 x 10⁸ = F x 1.95 x 10⁻¹¹
F = 
= 1.54 x 10¹⁹Hz
Energy of the photon is related to frequency using the expression below;
E = hF
h is the Planck's constant = 6.634 x 10⁻³⁴m²kg/s
Insert the parameters and solve;
E = 6.634 x 10⁻³⁴ x 1.54 x 10¹⁹ = 1.02 x 10⁻¹⁴J
The answers include the following:
- Graphite conducts electricity because it has delocalised electrons which makes it possible for the electrons to move freely.
- Graphite is slippery because it has layers which makes it possible for the atoms to slide over each other.
<h3>What is Graphite?</h3>
This is referred to as an allotrope of carbon and it is the most stable form. it is used in the production of substances such as pencil, electrode etc.
Graphite is able to conduct electricity because of the presence of delocalized electrons and is slippery due to its atoms being able to slide over one another.
Read more about Graphite here brainly.com/question/27860158
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The germ theory of disease
eventually led to the development of certain types of vaccines. This theory explains
that specific type or types of microorganisms, which are bacteria, virus, fungi,
or protest species, cause some diseases. These organisms can enter the human
body, and can even grow and reproduce, causing infection, inflammation to
specific organs in the body, and others. One particular vaccine developed successfully
through this understanding is the smallpox vaccine, which is an important
vaccine up to this day.
Answer: either B, or D
Explanation:
because one of those are the answer
Answer:
The correct option is the second option
Explanation:
Generally, the aim of science is to understand a particular concept in the best and the most correct way possible; hence experiments are done and repeated to ensure an explanation is actually true about a concept or need modification.
The atomic models have also been a "beneficiary" of this process. The different atomic models are usually been improved upon as scientists leaned more. For example, the Dalton's atomic theory has been modified to a more correct atomic description; some of which are shown below
(1) Dalton's theory suggested that an atom is the smallest unit of a molecule. We know now from different experiments (by J. J Thompson and Rutherford) that atoms are not the smallest molecules and are made up of smaller particles known as protons, neutrons and electrons.
(2) Dalton's theory suggested that atoms of the same elements are alike in all aspects. The knowledge of isotopy shows this is not always the case. As atoms of the same elements (isotopes) have the same atomic number but different mass number; hence cannot be said to be the same in all aspects.
(3) Dalton's theory also suggested that when atoms react, they do so in fixed, simple whole number ratio. The knowledge of organic chemistry shows atoms do not always react in simple whole number ratios
There are several modifications to different postulations by scientists that have also occurred aside from this, hence the most correct answer is that "As scientists learned more, they modified the atomic model"
