Practice: Calculate the energy (in nJ) of a photon emitted by a mercury lamp with a frequency of 6.88 x 10^{14} Hz.

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Wavelength and Frequency | 4 mins | 0 completed | Learn |

Speed of Light | 8 mins | 0 completed | Learn |

The Energy of Light | 13 mins | 0 completed | Learn |

Electromagnetic Spectrum | 11 mins | 0 completed | Learn Summary |

Photoelectric Effect | 14 mins | 0 completed | Learn Summary |

De Broglie Wavelength | 9 mins | 0 completed | Learn |

Heisenberg Uncertainty Principle | 14 mins | 0 completed | Learn |

Bohr Model | 15 mins | 0 completed | Learn |

Emission Spectrum | 6 mins | 0 completed | Learn |

Bohr Equation | 13 mins | 0 completed | Learn Summary |

Introduction to Quantum Mechanics | 5 mins | 0 completed | Learn Summary |

Quantum Numbers: Principal Quantum Number | 4 mins | 0 completed | Learn |

Quantum Numbers: Angular Momentum Quantum Number | 7 mins | 0 completed | Learn |

Quantum Numbers: Magnetic Quantum Number | 5 mins | 0 completed | Learn |

Quantum Numbers: Spin Quantum Number | 2 mins | 0 completed | Learn |

Quantum Numbers: Number of Electrons | 4 mins | 0 completed | Learn |

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Additional Practice |
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Diffraction vs Refraction |

Quantum Numbers: Emission Spectrum |

Dimensional Boxes |

The **Energy of Light **involves the use of a new variable *Planck's Constant*.

Example #1: Calculate the energy of a photon with a wavelength of 293.7 m.

Example #2: Calculate the energy for a mole of photons with a frequency of 4.29 x 10^{15} s^{-1}.

Practice: Calculate the energy (in nJ) of a photon emitted by a mercury lamp with a frequency of 6.88 x 10^{14} Hz.

Practice: A light ray has a wavelength that is 835 µm contains 6.32 x 10^{-3} J of energy. How many photons does this light ray have?

Practice: How much energy (in kJ) do 4.50 moles of photons contain at a wavelength of 705 nm?

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Concept #1: The Energy of Light

Concept #2: The Energy of Light

Example #1: The Energy of Light Example 1

Concept #3: The Energy of Light

Example #2: The Energy of Light Example 2

Practice #1: The Energy of Light Practice 1

Practice #2: The Energy of Light Practice 2

Practice #3: The Energy of Light Practice 3

The binding energy of an electron in iron is 7.49 × 10 –19 J. What is the maximum wavelength of light that can be used to eject electrons from iron?
A) 265 nm
B) 636 nm
C) 542 nm
D) 339 nm
E) 800 nm

For light with a wavelength of 12.5 nm, determine the energy of light in kJ/mol.
A. 4.99 * 10−18
B. 0.00957
C. 4.99
D. 9.57
E. 9570

What is the wavelength of a particle that has an energy of 4.41 × 10 –19 J?
a) 441 nm
b) 450 nm
c) 227 nm
d) 222 nm
e) 199 nm

What is the frequency (Hz) of an infrared light that emits 24.5 kJ/mol of energy?
a) 3.70 × 10 34
b) 6.14 × 10 13
c) 4.92 × 10 19
d) 8.17 × 10 –8
e) 2.70 × 10 –35

Ultraviolet light emits a total of 2.5 × 10 –17 J of light at a wavelength of 9.8 × 10 –7 m. How many photons does this correspond to?
a) 1
b) 10
c) 25
d) 100
e) 125

Blu-ray DVDs are read with a laser that has a wavelength of 405 nm. Calculate the energy of one mole of photons from this type of laser.
(a) 345 kJ
(b) 2.96×10 5 J
(c) 3.38×10 −6 J
(d) 4.91×10 −19 J
(e) 4.73×10 4 J

How much energy is contained in 2.5 moles of 455 nm photons?

A photovoltaic cell converts light into electrical energy. Suppose a certain photovoltaic cell is only 63.5% efficient, in other words, that 63.5% of the light energy is ultimately recovered. If the energy output of this cell is used to heat water, how many 520 nm photons must be absorbed by the photovoltaic cell in order to heat 10.0 g of water from 20.0°C to 30.0°?

In 1.0 s, a 60 W bulb emits 11 J of energy in the form of infrared radiation (heat) of wavelength 1850 nm. How many photons of infrared radiation does the lamp generate in 1.0 s?
1. 6.82 x 10 –14 photons
2. 1.04 x 10 29 photons
3. 6.63 x 10 23 photons
4. 1.10 x 10 –19 photons
5. 1.02 x 10 20 photons

A mixture of argon and mercury vapor used in advertising signs emits light of wavelength 560 nm.
Calculate the energy change resulting from the emission of 1.00 mol of photons at this wavelength.
1. 272.058
2. 184.162
3. 187.04
4. 213.759
5. 249.386
6. 217.646
7. 299.263
8. 199.509
9. 221,677
10. 225.859

Electromagnetic radiation with a wavelength of 525 nm appears as green light to the human eye. The energy of one photon of this light is __________ J.
A) 3.79 ×10-28
B) 2.64 ×1018
C) 1.04 × 10-22
D) 1.04 × 10-31
E) 3.79 ×10-19

How many photons are contained in a burst of yellow light (589 nm) from a sodium lamp that contains 609 kJ of energy?
A) 3.06 × 1030 photons
B) 2.48 × 1025 photons
C) 1.81 × 1024 photons
D) 3.37 × 1019 photons
E) 4.03 × 1028 photons

How much energy (in kJ) do 3.0 moles of photons, all with a wavelength of 655 nm, contain?
A) 303 kJ
B) 394 kJ
C) 254 kJ
D) 548 kJ
E) 183 kJ

Calculate the energy in kJ/mol of light with a wavelength of 360 nm.
A) 332 kJ/mol
B) 5.52 × 10-19 kJ/mol
C) 0.332 kJ/mol
D) 5.52 × 10-22 kJ/mol
E) 6.63 × 103 kJ/mol

How many photons of light with frequency 5.50 × 10 15 Hz are required to provide 1 kJ of energy?
A) 2.74 × 1020 photons
B) 3.64 × 10-16 photons
C) 3.64 × 10-18 photons
D) 4.56 × 10-4 photons
E) 1.65 × 1044 photons

What is the energy in joules of a mole of photons with the energy of the 434 nm spectral line of hydrogen?
A) 5.78 × 10-25 J
B) 2.76 × 10-4 J
C) 434 J
D) 9.21 × 10-4 J
E) 2.76 × 105 J

Carbon emits photons at 745 nm when exposed to blackbody radiation. How much energy would be obtained if 44g of carbon were irradiated? Assume each carbon atom emits one photon.
a. 9.1 x 10 5 J
b. 2.7 x 10 -19 J
c. 7.1 x 10 6 J
d. 5.9 x 10 5 J

The energy of a photon is
1. nλ.
2. cλ.
3. c/λ .
4. λ/hc .
5. hc/λ .

A low-pressure mercury-vapor lamp has a characteristic emission line at 253 nm. Knowing that this lamp is putting out 11.8 watts of light energy, how many mercury atoms are emitted per second during operation?
1. 5.25 x 1020 atoms
2. 7.11 x 1024 atoms
3. 1.50 x 1019 atoms
4. 1.08 x 1017 atoms
5. 7.86 x 10−19 atoms
6. 4.73 x 105 atoms

It takes 238 kJ/mol to break a carbon-iodine bond. Calculate the frequency of light for which one carbon-iodine bond could be broken by absorbing a single photon.
a) 5.03 x 10-7s-1
b) 5.96 x 1011 s-1
c) 3.59 x 1035 s-1
d) 3.59 x 1038 s-1
e) 5.96 x 1014 s-1

How many photons of light with frequency 5.50 x 10 15 Hz are required to provide 1 kJ of energy?A. 1.65 x 10 44 photonsB. 2.74 x 10 20 photonsC. 3.64 x 10 -16 photonsD. 3.64 x 10 -18 photonsE. 4.56 x 10 -4 photons

How much total energy (in MJ/mol) would it take to remove the electrons from a mole of hydrogen atoms?
The ionization energy for a hydrogen atom is 2.178 x 10-18 J.
(A) 3.617 x 10 -42 MJ
(B) 1.312 MJ
(C) 2.765 MJ
(D) 1.312 x 10 6 MJ
(E) 2.765 x 10 35 MJ

Medical applications of electromagnetic radiation cover the entire spectrum, from gamma rays used to diagnose and treat cancer, to radio waves used in magnetic resonance imaging (MRI). Until recently the tools did not exist to exploit the range from 0.1 to 10 THz, leading some to call this region of the spectrum from 0.1 to 10 THz the “terahertz gap.” But that gap is starting to close as new techniques are developed to explore the terahertz region of the spectrum (Chemistry & Engineering News, 2015, 93, 10-14). It was discovered the terahertz light causes groups of water molecules to coalesce and disassemble repeatedly, and because water permeates most biological studies, terahertz spectroscopy holds considerable promise as important new tool in medical science. A. Calculate the energy (in J) of a 2.4 THz photon.(1 THz = 1 x 1012 Hz = 1 x 1012 s -1 ) Convert your answer above from J to kJ/mol. B. Calculate the wavelength (in nm) of a 2.4 THz photon. Do you expect 2.4 THz light to be dangerous to biological tissue? Explain your reasoning.

A. Calculate the energy of a photon with a wavelength of 100 nm. Convert the energy to units of kJ/mol. Is this photon within the region for visible light, higher in energy, or lower in energy? ________________B. How would you calculate the speed of hydrogen atom with a wavelength of 1.00 nm? Set up the equation, including conversion factors, but do not do the calculation.

What is the energy of a photon of ultraviolet radiation, λ= 500 pm?a) 1.11 x 10-49 Jb) 1.67 x 10-16 Jc) 9.95 x 10-33 Jd) 3.98 x 10-16 Je) 7.24 x 10-12 J

If the frequency of an X-ray is 5.4 x 10 18 Hz, what is the energy of one photon of this radiation?
a) 3.6 x 10-15 J
b) 1.6 x 10-27 J
c) 1.2 x 10-52 J
d) 2.7 x 10-10 J
e) 7.4 x 10-29 J

The existence of discrete (quantized) energy levels in an atom may be inferred from (A) experiments on the photoelectric effect.(B) diffraction of electrons by crystals.(C) X-ray diffraction by crystals(D) atomic line spectra

A red laser pointer emits light with a wavelength of 650 nm. (b) What is the energy of one of these photons?

If you put 120 volts of electricity through a pickle, the pickle will smoke and start glowing an orange-yellow color. The light is emitted because the sodium ions in the pickle become excited; their return to the ground state results in light emission (see Figure 6.13b and Sample Exercise 6.3). (b) What is the energy of 0.10 mole of these photons?

An AM radio station broadcasts at 1010 kHz, and its FM partner broadcasts at 98.3 MHz. Calculate and compare the energy of the photons emitted by these two radio stations.

One type of sunburn occurs on exposure to UV light of wavelength in the vicinity of 325 nm. (a) What is the energy of a photon of this wavelength?

One type of sunburn occurs on exposure to UV light of wavelength in the vicinity of 325 nm. (b) What is the energy of a mole of these photons?

One type of sunburn occurs on exposure to UV light of wavelength in the vicinity of 325 nm. (c) How many photons are in a 1.00 mJ burst of this radiation?

One type of sunburn occurs on exposure to UV light of wavelength in the vicinity of 325 nm. (d) These UV photons can break chemical bonds in your skin to cause sunburn—a form of radiation damage. If the 325-nm radiation provides exactly the energy to break an average chemical bond in the skin, estimate the average energy of these bonds in kJ/mol.

Sodium metal requires a photon with a minimum energy of 4.41 x 10 -19 J to emit electrons. (a) What is the minimum frequency of light necessary to emit electrons from sodium via the photoelectric effect?

Sodium metal requires a photon with a minimum energy of 4.41 x 10 -19 J to emit electrons. (b) What is the wavelength of this light?

Sodium metal requires a photon with a minimum energy of 4.41 x 10 -19 J to emit electrons. (d) What is the maximum number of electrons that can be freed by a burst of light whose total energy is 1 .00 μJ?

A photon from a indigo laser has a wavelength of 465 nm. What is the energy of a photon from this laser?a. 4.3 x 10-28 Jb. 3.08 x 10-31 Jc. 1.4 x 10-27 Jd. 4.27 x 10-19 Je. 1.79 x 10-18 J

What is the energy in joules of a mole of photons with the energy of the 434 nm spectral line of hydrogen?A) 5.78 × 10-25 JB) 2.76 × 10-4 JC) 434 JD) 9.21 × 10-4 JE) 2.76 × 105 J

Calculate the energy of the orange light emitted by a neon sign with a frequency of 4.89 × 1014 Hz.
A) 5.11 × 10-19 J
B) 3.09 × 10-19 J
C) 6.14 × 10-19 J
D) 1.63 × 10-19 J
E) 3.24 × 10-19 J

The absorption of light of frequency 1.16 × 10 11 Hz is required for CO molecules to go from the lowest rotational energy level to the next highest rotational energy level. Determine the energy for this transition in kJ/mol. h = 6.626 × 10-34 J ∙ s
A) 7.69 ×10-23 kJ/mol
B) 46.3 kJ/mol
C) 949 kJ/mol
D) 0.0463 kJ/mol

Use Planck's equation to determine the energy, in J/photon, of radiation of frequency 5.8 × 1015 s-1.
A) 5.8 ×10-25 J
B) 1.7 ×10-16 J
C) 3.8 ×10-18 J
D) 5.2 ×10-8 J
E) 1.7 ×1024 J

It takes light with a wavelength of 212 nm to break the NH bond in ammonia. What energy is required and what is the NH bond strength?1. 6.6×10−22 kJ/photon, 4 × 10−4 kJ/mol2. 9.4 × 10−19 kJ/photon, 565 kJ/mol3. 9.4 × 10−22 kJ/photon, 565 kJ/mol 4. 6.6 × 10−22 kJ/photon, 0.40 kJ/mol5. 9.4 × 10−22 kJ/photon, 565,000 kJ/mol

My microwave operates at a wavelength of 300.0 mm (note units). What is the energy of a mole of photons generated by this microwave? The value of Planck’s constant, h = 6.63 x 10-34 J s.a. 4.3 kJb. 4.3 x 10-5 kJc. 330 kJd. 4.0 x 10-4 kJe. 5.5 x 10-25 kJ

One type of ultraviolet light has a wavelength of 223 nm. Calculate the energy of one photon of this light.a. 8.91 x 10 -19 Jb. 6.95 x 10 -19 Jc. 7.12 x 10 -19 Jd. 7. 87 x 10 -19 J

An ultraviolet (UV) light photon has a wavelength of 124.1 nm. What is its energy in joules?

What is the energy (in kJ/mol) of red photons with a frequency equal to 4.00 x 10 14 Hz?A. 5.30 x 102 B. 1.60 x 102C. 480 x 102 D. 480 x 103 E. 5.30 x 103

What is the energy (J) of a photon of a 1 km radio wave?
a) 1 x 10-25
b) 1 x 10-28
c) 2 x 10-25
d) 2 x 10-28
e) 5 x 10-25

A laser pulse produces 1.046 kJ of energy. It was experimentally determined that the pulse contains 3.50 x 1022 photons. Determine the wavelength of light (in meters) emitted by one photon.
A) 6.65 x 10-3 m
B) 1.50 x 105 m
C) 5.43 x 10-48 m
D) 1.50 x 102 m
E) 6.65 x 10-6 m

What is the wavelength of light if the energy of a photon is 3.65 x 10 -19 J?
A) 545 nm
B) 5.45 x 10-7 nm
C) 1.84 x 106 nm
D) 5.51 x 1014 nm
E) 654 nm

The energy of a photon of light is given by E = hv. The frequency, v, of light and the wavelength, λ, are related through: v = c/λ where c is the speed of light, 2.998 x 108 m/s. Arrange the following wavelengths of light from lowest energy to highest energy: 461 nm, 637 nm, 517 nm. What is the energetic of a photon light with a wavelength of 415 nm?

Hospital X-ray generators emit X rays with wavelength of about 15.0 nm, where 1 nm = 10 -9 m. What is the energy of a photon in an X ray? Express answer in joules.

Calculate the energy of a photon of electromagnetic radiation at each of the following wavelengths.i) 632.8 nm (wavelength of red light from helium-neon laser) ii) 503 nm (wavelength of maximum solar radiation) iii) 0.0520 nm (a wavelength contained in medical X-rays)

How many photons are contained in a flash of green light (525 nm) that contains 189 kJ of energy?

Calculate the energy of a photon of electromagnetic radiation at each of the following frequencies.i) 102.3 mHz (typical frequency for FM radio broadcasting) ii) 1055 kHz (typical frequency for AM radio broadcasting) (assume four significant figures) iii) 835.6 MHz (common frequency used for cell phone communication)

Which of the following occur as the energy of a photon increases?a. The frequency decreases.b. The speed increases.c. The wavelength increases.d. The wavelength gets shorter.e. None of the above.

The energy of a photon that has a wavelength of 9.0 m is _____ J. a. 2.2 x 10-26 b. 4.5 x 1025 c. 6.0 x 10-23 d. 2.7 x 109 e. 4.5 x 10-25

A 1.00 mL ampule of a 0.150 M solution of naphthalene in hexane is excited with a flash of light. The naphthalene emits 19.9 J of energy at an average wavelength of 349 nm.What percentage of the naphthalene molecules emitted a photon?

In fireworks, the heat of the reaction of an oxidizing agent, such as KClO4, with an organic compound excites certain salts, which emit specific colors. Strontium salts have an intense emission at 641 nm, and barium salts have one at 493 nm. What is the energy (in kJ) of these emissions for 5.00 g each of the chloride salts of Sr and Ba? (Assume that all the heat produced is converted to emitted light.)

A Blu-ray laser has a power of 5 milliwatts (1 watt = 1 J s−1). How many photons of light are produced by the laser in 1 hour? (λ = 405nm.)

The energy from radiation can be used to cause the rupture of chemical bonds. A minimum energy of 242 kJ/mol is required to break the chlorine–chlorine bond in Cl2.What is the longest wavelength of radiation that possesses the necessary energy to break the bond?

Determine the energy of 1.60 mol of photons for each of the following kinds of light. (Assume three significant figures.)infrared radiation (1510 nm)

Photons of infrared radiation are responsible for much of the warmth we feel when holding our hands before a fire. These photons will also warm other objects. How many infrared photons with a wavelength of 1.5 × 10−6 m must be absorbed by the water to warm a cup of water (175 g) from 25.0 °C to 40 °C?

The optic nerve needs a minimum of 2.0 x 10−17 J of energy to trigger a series of impulses that eventually reach the brain. How many photons of blue light (475 nm) are needed?

The power of a red laser (λ = 630 nm) is 2.50 watts (abbreviated W, where 1 W = 1 J/s). How many photons per second does the laser emit?

Calculate the frequency (Hz) and energy (J/photon) of visible light with a wavelength of 325nm.

Calculate the energy of a photon of electromagnetic radiation at each of the following frequencies (in J).i) 103.7 MHz (typical frequency for FM radio broadcasting)ii) 1100 kHz (typical frequency for AM radio broadcasting) (assume four significant figures)

Suppose that the microwave radiation has a wavelength of 12.4 cm. How many photons are required to heat 215 mL of coffee from 25.0 degree C to 62.0° C? Assume that the coffee has the same density, 0.997 g/mL, and specific heat capacity, 4.184 J/(g• K), as water over this temperature range. Express the number of photons numerically.

How many photons are contained in a flash of green light (525 nm) that contains 189 kJ of energy?(a) 4.99 x 1023(b) 7.99 x 1030(c) 5.67 x 1023(d) 1.25 x 1031(e) 3.75 x 1023

The human eye contains a molecule called 11-cis-retinal that changes conformation when struck with light of sufficient energy. The change in conformation triggers a series of events that results in an electrical signal being sent to the brain. The minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kJ/mol.Calculate the longest wavelength visible to the human eye.

The energy of light calculated using the formulas below tell you the energy per photon of light. E = h x v E = h x c / λ If light has a wavelength of 789 nm, what is the energy of this light expressed in kJ/mol?

Which of the following wavelengths of light has the highest energy?i) 4.0 x 10-4 mii) 3.8 x 10-9 miii) 9.2 x 105 miv) 7.3 x 101 mv) 1.5 x 10-14 m

A certain shade of blue has a frequency of 7.01 x 1014 Hz. What is the energy (J) of exactly one photon of this light?

It takes 157 kJ/mol to break a nitrogen-oxygen single bond. Calculate the maximum wavelength of light (nm) for which a nitrogen-oxygen single bond could be broken by absorbing a single photon.

What is the wavelength λ of the photon that has been released with ΔE = -2.05 x 10-18 J? Express your answer with the appropriate units.

How much energy is contained in 1 mol of each of the following? a. X-ray photons with a wavelength of 0.135 nm. Express the energy numerically in kilojoules per mole. b. γ-ray photons with a wavelength of 2.38×10−5 nm. Express the energy numerically in kilojoules per mole.

Be sure answer all parts.How many photons at 586 nm must be absorbed to melt 5.15 x 10 2 g of ice? (It takes 334 J to melt 1 g of ice at 0°C.) (Enter your answer in scientific notation.) On average, how many H2O molecules does one photon convert from ice to water? (Enter your answer in scientific notation.)

Part AX-ray photons with a wavelength of 0.135 nm. Express the energy numerically in kilojoules per mole. Part Bγ-ray photons with a wavelength of 2.60 x 10-5 nm. Express the energy numerically in kilojoules per mole.

Where h = 6.626 x 10 -34 J s ( Planck's constant ) and c = 2.99 x 10 8 m/s. What is the wavelength of a photon that has an energy of E = 4.13 x 10-19 J? (in meters). The equation for photon energy E is?

Calculate the energy of a photon of electromagnetic radiation at each of the following frequencies. Express your answer using four significant figures.a. 104.2 MHz (typical frequency for FM radio broadcasting)b. 1070 kHz (typical frequency for AM radio broadcasting) (assume four significant figures)c. 835.6 MHz (common frequency used for cell phone communication)

How many photons are produced in a laser pulse of 0.528 J at 679 nm?

Ionization involves completely removing an electron from an atom. Light of a particular wavelength can cause ionization to occur if it has the required energy. The energy to ionize a certain element is 530 kJ/mol. What wavelength contains enough energy in a single photon to ionize one atom of this element? Enter your answer with three significant figures.

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