What is the energy of a photon emitted with a wavelength of 571 nm?


Answer 1
Answer: E=h * nu, where nu is frequency of the wave.
frequency = 1/wavelength = 1/571 *10 ^-9 = 1.7 * 10^7.

e= 6.63 *10^-34 *1.7 *10^7

e=11.271 * 10^-27 Joules

Related Questions


an unknown compound was determined to be 74.97% carbon, 8.39% hydrogen, and 16.64% oxygen. calculate the empirical formula





Empirical Formula: This is the simplest formula of a compound.

From the question,

Percentage by mass of the elements: C = 74.97%, H = 8.39%, O = 16.64%

Molar mass of the elements : C = 12 g/ mole, H = 1 g/mole, O = 16 g/mole

Step 1: Divide the percentage by mass by the molar mass

 C                       :         H                   :           O

 74.97/12                   8.39/1                     16.64 /16

6.2475               :       8.39                :          1.04

Step 2: Dived by the smallest ratio ( 1.04)

C                         :        H                   :              O

6.2475/1.04        :      8.39/1.04        :              1.04/1.04

6                          :      8                     :               1

Hence, The empirical formula of the compound = C₆H₈O


The empirical formula of the unknown compound is C₆H₈O


The simplest ratio (whole number) of the atoms in a compound is the empirical formula of the compound.

To determine the empirical formula of the compound given, the following steps are followed;

(i). Since percentage compositions of the elements in the compound are given, it can be assumed that all calculated from 100 grams of the compound. Therefore, the percentages can be changed directly to grams as follows;

74.97% Carbon (C) => 74.97g of Carbon (C)

8.39% Hydrogen (H) => 8.39g of Hydrogen (H)

16.64% Oxygen (O) => 16.64g of Oxygen (O)

(ii) Convert the grams to corresponding number of moles;

Recall that;

1 mole of Carbon contains 12 grams of the atom

=> 74.97 grams will be   moles of Carbon

=> 74.97 grams will be  6.2475 moles of Carbon


1 mole of Hydrogen atoms contains 1 gram of the atom

=> 8.39 grams will be   moles of Hydrogen

=> 8.39 grams will be  8.39 moles of Hydrogen


1 mole of Oxygen atoms contains 16 grams of the atom

=> 16.64 grams will be   moles of Hydrogen

=> 16.64 grams will be  1.04 moles of Hydrogen

(iii) Normalize the results calculated in step (ii) above by dividing each by the smallest (which is 1.04)

                               |     Carbon          |     Hydrogen         |         Oxygen

Moles                      |      6.2475          |      8.39                 |          1.04

Divide by smallest |     = 6.007  |        = 8.07       |           = 1

(iv) Round off the results in (iii) above to the nearest unit

                               |     Carbon          |     Hydrogen         |         Oxygen

Moles                      |      6.2475          |      8.39                 |          1.04

Divide by smallest |     = 6.007  |        = 8.07       |           = 1

Rounding off          |       6                   |        8                    |           1

(v) Derive the empirical formula

By using the numbers resulting from step (iv) as subscript, place them beside each of their corresponding elements as follows;

=> C₆H₈O₁

The number 1 (which is the subscript of Oxygen can be removed)

=> C₆H₈O

Therefore, the empirical formula of the unknown compound is C₆H₈O


Which gas law states that the pressure of a gas decreases when volume is increased and the temperature is unchanged? A. Charles' Law
B. Boyle's Law
C. The General Gas Law
D. The Law of Cubic Expansion


Which gas law states that the pressure of a gas decreases when volume is increased and the temperature is unchanged?

A. The General Gas Law

B. The Law of Cubic Expansion

C. Charles' Law

D. Boyle's Law


A horizontal surface of area 0.321 m2has an electric flux of 123 N.m2/C passing through it at an angle of 25° to the horizontal. If the flux is due to a uniform electric field, calculate the magnitude of the latter.



electric filed is 907 N/C


Given data

surface of area = 0.321 m²

electric flux of 123 N.m²/C

angle = 25°

to find out

magnitude of the electric field


we know flux formula that is

flux = electric filed × area

put all value

123 = electric filed × 0.321 sin(25)

electric filed = 123 /  0.321 sin(25)

electric filed = 906.67

so electric filed is 907 N/C


Some species of jellyfish use jet propulsion to get around, a much gentler form of jet propulsion than squid use. A small jellyfish takes water into its bell; the total mass of jellyfish and water is 3.2 g. It then rapidly ejects 1.3 g of water, achieving a speed of 0.070 m/s. What is the speed of the ejected water?



speed of ejected out water will be 0.102 m/s


Initially the jellyfish is given at rest

so here since there is no external force on the system of jelly fish and the water in it so the momentum of the whole system will remains conserved

so here we have

initial momentum is zero

now final momentum of both will also be zero

so here we have

so we have

so speed of ejected out water will be 0.102 m/s


What were the results of European colonization of central Africa? A. Africans were forced to work on plantations.

B. Europeans controlled the government of central Africa.

C. European countries made little economic gain from the colonies.

D. Millions of Africans died in the Congo due to mistreatment.

Note: this is a multiple choice questions.


Africans were forced to work on plantations and millions of Africans died in the Congo due to mistreatment were the results of European colonization of central Africa.

Results of European colonization of central Africa

Colonialism creates a large impact on the lives of Africans. They were made labours which work for eurpeans for the plantation. Millions of african people died due to bad treatment of Europeans.

So we can conclude that option A and D are correct answers.

Learn more about colonization here:


Planting of crops to purify -lucern, shrubs, trees(possible job creation)


Those plants was used to clean toxic substance in the environment

In our current time, those crops had became a very important commodity and could potentially be used to generate profit if you handle it seriously an created several job opportunities in the process

hope this helps

Plants are a noteworthy method for water decontamination. Plants, for example, Lucerne and bushes have a high affinity for water. They retain water from the dirt together with the contaminants.

Further Explanation

Purification of water using plants

The purification of water from plants is the same old thing. The earth is continually utilizing both soil and vegetation to wash down itself. Water is a functioning liquid. It is consistently moving and is being used by plants, soil, mists, truly everything. As water ignores through and plants roots and leaves, the fluid is ingested into the plant's tissues. There is a characteristic cycle wherein water is first ingested then discharged from the plant's leaves and roots.  

Such plants, for example, Reed, Bur-Reed, Sedges, Water Lily, etc.

Sweet flag and water soldier have the ability to reuse water through their root system.

Using plants purifying of water from wastes

Plants remove from water

  1. Heavy metals  
  2. Parasites  
  3. Harmful microorganisms  
  4. Radio dynamic isotopes (permeable carbon and green coal work much superior to plants).
  5. Chemicals  

Cysts (with time (the sores pull in themselves to the plant roots with a delayed introduction (this technique isn't 100%).

Obviously, once the contaminants are consumed by the plants many will address how to discard them.  

To begin with, a portion of the consumed waste will normally break down with the plant. In any case, synthetic compounds, radio dynamic isotopes, and overwhelming metals will require exceptional treatment when the plants kick the bucket.  

Another technique for dealing with this plant waste is to utilize mushroom spores. Mushrooms produce a slim threadlike system of roots called mycelium and mycelium produces compounds that separate a considerable number of "nasties" (contaminants). So basically, we utilize a plant to clean a plant.

Answer details

Subject: Physics

Level: High School


  • Purification of water using plants
  • Purification of water using plants

How does the frequency of sound relate to its pitch?


Good afternoon!
the answer to that particular question is this
a particular pitch directly corresponds to frequency in that if you have a pitch you will have a high frequency
if you a low frequency you will have a low pitch
both are intertwined in marriage!

Please help fast!! A skateboarder traveling at 10.4 m/s starts getting chased by a grumpy dog. The skateboarder speeds up with a constant acceleration for 39m over a 3.3s. We want to find the acceleration of the skateboarder over the 3.3s time interval.

Which kinematic formula would be most useful to solve for the target unknown?

Picture shows answer choices better.
A. V= Vo+a(t)
B. X= (V+Vo/2)t
C. X= Vo(t)+1/2at^2
D. V^2 = Vo^2 +2ax
E. X= vt-1/2at^2


The answer is C..........      


Interference is a condition that occurs when _____. a) one side of a wave moves at a different speed than the other

b) a wave encounters an obstruction

c) two or more waves overlap and combine

d) the source of the wave’s vibration loses energy


For the answer to the question above, To set up a stable and clear interference pattern, two conditions must be met: The sources of the waves must be coherent, which means they emit identical waves with a constant phase difference. So I think the answer is c.two or more waves overlap and combine.
Because waves needs to be monochromatic or in single wavelength
Random Questions
Ppplleeaassee help me: Assignment Directions: You will write a summary of the non-fiction article Robots On Earth. View the grading rubric before you start your work. This is your guide to a super submission. (See below) 1. Copy and paste the entire text of the article into a document. (done) Robots on Earth by Jerry West (INTRO) Explosions. Car chases. A man and woman, drenched in sweat, limping from a building as it crumbles to the ground, muster the last of their strength to rescue humanity from its inevitable extinction at the cold, metal hands of humanoid creatures with artificial intelligence gone awry. For decades, books and movies have dictated how we think of robots. Simply the word "robot" can bring to mind images of evil, mechanical creatures bent on taking over the world and wiping out every glimmer of humanity. And yet, the truth of machines is dramatically different. Today's robots hold little in common with their villainous cousins from action-packed science fiction. Most robots have no interest in harming the human population at all; they exist to aid people in making life safer, healthier, and more productive. (PARAGRAPH #1) For example, jobs such as welding and painting are important to civilization as we know it, but experience has taught us that these activities can be hazardous to human health. In addition, fumes in automobile and airplane factories can harm organic bodies that become exposed to their toxins in the assembly process. Even when the best precautions are taken, workers may still suffer from lack of adequate ventilation. What is the answer to these difficult dilemmas? Robots. Because machines don't rely on clean air or comfortable temperatures, because they can function even in the midst of deadly gasses, they can take over with ease where humans would suffer greatly. Working together, humans and robots can get the job done. (PARAGRAGRAPH #2) A robot's job isn't limited to the terrestrial level, either. Even in space, machines such as the R2 humanoid robot at the International Space Station complete dangerous tasks for astronauts, protecting them from potentially deadly situations. And then, when there are mundane but essential tasks to conduct on the space station, R2 takes care of those, as well, freeing up the astronauts' time for more important responsibilities. Thus, in space and on Earth, robots manage to create healthier, happier humans. (PARAGRAPH #3) In fact, there are robots on Earth that exist specifically to boost human health. Just as contact lenses enhance human sight, robotics can increase human mobility. People with disabilities and various forms of paralysis now have hope that they can achieve better range of motion, when before this wasn't possible. With the help of robots, scientists are working to create an exoskeleton that will attach itself to the outside of the human body, establishing a connection to the human brain. Neuroscientist Miguel Nicolelis has a dream. "We are working with the Brazilian government, who is helping fund the project. At the 2014 soccer World Cup celebrations we hope to have a Brazilian teenager with quadriplegia walk out and make the opening kick." (CONCLUSION) Explosions and car crashes may sell tickets for the summer blockbuster, but robots have so much more to offer, and much of it is positive service to humans. At the heart of the field of robotics is not the creation of people-destroying machines with evil artificial intelligence, but something much more useful. Robots aren't our enemies; instead, they are the valuable result of scientific endeavors to create safer lives for people everywhere. 1. Write a main idea sentence for each paragraph of the article, Robots on Earth. Intro: Paragraph #1: Paragraph #2 (write 2 sentences here): Paragraph #3 (write 2 sentences here): Conclusion: 4. Write YOUR summary paragraph of Robots on Earth HERE (for full credit it needs to be 7 sentences):