Will a photoelectric effect be observed in potassium when illuminated with a frequency $6\cdot10^{14}\,\text{Gts}$, if the work function is greater than the photon energy?

E_{\text{F}} = 3{,}96\cdot 10^{-19}\,\text{J} > A\ \text{— photoeffect there will be}

Solar radiation power $4\cdot10^{23}\,\text{kVt}$. How much does the mass of the Sun decrease per day?

\Delta m = 3{,}84\cdot 10^{14}\,\text{kg}

What impulse is transmitted to the mirror by a photon with wavelength $2{,}95\cdot10^{-7}\,\text{m}$ with normal reflection?

\Delta p = 4{,}47\cdot 10^{-27}\,\tfrac{\text{kg}\cdot\text{m}}{\text{s}}

Solar radiation power $4\cdot10^{26}\,\text{Vt}$. Determine the flux density of solar radiation on Earth. Distance $1{,}5\cdot10^{11}\,\text{m}$.

I = 1400\,\tfrac{\text{W}}{\text{m}^{2}}

What wavelength of light should be directed onto a tungsten plate so that electrons are ejected at the speed $8\cdot10^{5}\,\text{m/s}$? Determine red limit and delay voltage when operating output $4{,}95\,\text{eV}$.

\lambda = 1{,}83\cdot 10^{-7}\,\text{m}; \lambda_0 = 2{,}5\cdot 10^{-7}\,\text{m}; U_{\text{z}} = 1{,}82\,\text{B}

Red border for metal $5{,}3\cdot10^{14}\,\text{Gts}$. Determine the maximum speed of photoelectrons at wavelength $5\cdot10^{-7}\,\text{m}$. Will there be a photoelectric effect when $6\cdot10^{-7}\,\text{m}$?

v_{\text{m}1} = 3{,}2\cdot 10^{5}\,\tfrac{\text{m}}{\text{s}}; v_{\text{m}2}\ \text{— photoelectric effect no}

Wavelength of light in glass $5\cdot10^{-7}\,\text{m}$, refractive index $1{,}5$. What is the wavelength in air and frequency?

\lambda = 7{,}5\cdot 10^{-7}\,\text{m}; \nu = 4\cdot 10^{14}\,\text{Hz}

X-ray tube is energized $45\,\text{kV}$. What is the minimum wavelength of X-rays?

\lambda_{\min} = 2{,}75\cdot 10^{-11}\,\text{m}

The photoelectric effect occurs only when the momentum of the incident photon is no less than $9\cdot10^{-28}\,\text{kg}\cdot\text{m/s}$. At what speed will electrons be ejected if the light frequency is twice the threshold?

v = 7{,}7\cdot 10^{5}\,\tfrac{\text{m}}{\text{s}}

The atom went from a state with energy $-1{,}5\,\text{eV}$ in a state $-5\,\text{eV}$. Determine the energy, frequency, wavelength, momentum, and equivalent mass of the emitted photon.

E_{\text{F}} = 3{,}5\,\text{eV}; \nu = 8{,}48\cdot 10^{14}\,\text{Hz}; \lambda = 3{,}54\cdot 10^{-7}\,\text{m}; p = 1{,}87\cdot 10^{-27}\,\tfrac{\text{kg}\cdot\text{m}}{\text{s}}; m = 6{,}2\cdot 10^{-36}\,\text{kg}

Gas laser wavelength $632{,}8\,\text{nm}$. Determine the frequency, energy, momentum, and equivalent mass of the photon.

\nu = 4{,}74\cdot 10^{14}\,\text{Hz}; E_{\text{F}} = 3{,}13\cdot 10^{-19}\,\text{J}; p = 1{,}04\cdot 10^{-27}\,\tfrac{\text{kg}\cdot\text{m}}{\text{s}}; m = 3{,}5\cdot 10^{-36}\,\text{kg}

Ionization energy of a hydrogen atom $13{,}6\,\text{eV}$. Is a photon with a wavelength capable of $4\cdot10^{-8}\,\text{m}$ ionize an atom?

E_{\text{F}} = 4{,}95\cdot 10^{-18}\,\text{J} > E_i\ \text{— capable}

11TH GRADE PRACTICE

Physics Problems: Quantum physics, Grade 11

Photons and the photoelectric effect.

17 problems across 1 sub-topics

Practise in the interactive mode

Here the conditions and analysis of the solution can be read without an account. In the simulator, you need to collect the same analyzes yourself: “Given,” formulas, order of steps and answer.

Problem statements

The answer options are there to check against, and the walkthrough opens under each problem.

17 problems

Position in this set: 1 from 17

Problem #61

Quantum physics and photoelectric effect

Determine the energy, equivalent mass and momentum of a violet photon with wavelength .

Answer options

Show the walkthroughHide the walkthrough

Given

Find

A photon has no rest mass; this is the equivalent mass corresponding to its energy.

Answer

Position in this set: 2 from 17

Problem #62

Quantum physics and photoelectric effect

Will a photoelectric effect be observed in potassium when illuminated with a frequency , if the work function is greater than the photon energy?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

The energy of a photon is enough to tear an electron out of a metal.

Answer

Position in this set: 3 from 17

Problem #63

Quantum physics and photoelectric effect

For the previous problem, take the work function . Determine the maximum kinetic energy and speed of photoelectrons, the retardation voltage, and the red limit of the photoelectric effect.

Answer options

Show the walkthroughHide the walkthrough

Given

Find

Einstein's equation for the photoelectric effect.
The red boundary is the longest wavelength at which the photoelectric effect is still possible.

Answer

Position in this set: 4 from 17

Problem #64

Quantum physics and photoelectric effect

Solar radiation power . How much does the mass of the Sun decrease per day?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

Answer

Position in this set: 5 from 17

Problem #65

Quantum physics and photoelectric effect

Determine the red limit of the photoelectric effect for zinc at work function .

Answer options

Show the walkthroughHide the walkthrough

Given

Find

Answer

Position in this set: 6 from 17

Problem #66

Quantum physics and photoelectric effect

What impulse is transmitted to the mirror by a photon with wavelength with normal reflection?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

During mirror reflection, the photon momentum changes sign, so double the momentum is transferred to the mirror.

Answer

Position in this set: 7 from 17

Problem #67

Quantum physics and photoelectric effect

Solar radiation power . Determine the flux density of solar radiation on Earth. Distance .

Answer options

Show the walkthroughHide the walkthrough

Given

Find

Flux density is the energy coming to 1 m² in 1 s.
All energy passes through a sphere of radius r.
This quantity is called the solar constant.

Answer

Position in this set: 8 from 17

Problem #68

Quantum physics and photoelectric effect

What wavelength of light should be directed onto a tungsten plate so that electrons are ejected at the speed ? Determine red limit and delay voltage when operating output .

Answer options

Show the walkthroughHide the walkthrough

Given

Find

The holding voltage depends only on the speed of the electrons.

Answer

Position in this set: 9 from 17

Problem #69

Quantum physics and photoelectric effect

Red border for metal . Determine the maximum speed of photoelectrons at wavelength . Will there be a photoelectric effect when ?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

There is not enough photon energy: at this wavelength there is no photoelectric effect.

Answer

Position in this set: 10 from 17

Problem #70

Quantum physics and photoelectric effect

At what speed must an electron move so that its momentum is the same as that of a photon with a wavelength ?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

The photon momentum is h/λ, the electron momentum is mv.

Answer

Position in this set: 11 from 17

Problem #71

Quantum physics and photoelectric effect

Wavelength of light in glass , refractive index . What is the wavelength in air and frequency?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

In the air, the wave is longer - this is red light.

Answer

Position in this set: 12 from 17

Problem #72

Quantum physics and photoelectric effect

X-ray tube is energized . What is the minimum wavelength of X-rays?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

The minimum wavelength is obtained when the electron gives all its energy to one photon.

Answer

Position in this set: 13 from 17

Problem #73

Quantum physics and photoelectric effect

The photoelectric effect occurs only when the momentum of the incident photon is no less than . At what speed will electrons be ejected if the light frequency is twice the threshold?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

The threshold of the photoelectric effect is specified through the pulse, but this is the same work function.

Answer

Position in this set: 14 from 17

Problem #74

Quantum physics and photoelectric effect

The atom went from a state with energy in a state . Determine the energy, frequency, wavelength, momentum, and equivalent mass of the emitted photon.

Answer options

Show the walkthroughHide the walkthrough

Given

Find

1 eV = 1.6·10⁻¹⁹ J.
Check: p = mc gives the same value of momentum.

Answer

Position in this set: 15 from 17

Problem #75

Quantum physics and photoelectric effect

Having energy , the atom emits a photon with frequency . What is the final energy of an atom?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

By emitting a photon, the atom descends to a lower level.

Answer

Position in this set: 16 from 17

Problem #77

Quantum physics and photoelectric effect

Gas laser wavelength . Determine the frequency, energy, momentum, and equivalent mass of the photon.

Answer options

Show the walkthroughHide the walkthrough

Given

Find

Answer

Position in this set: 17 from 17

Problem #90

Quantum physics and photoelectric effect

Ionization energy of a hydrogen atom . Is a photon with a wavelength capable of ionize an atom?

Answer options

Show the walkthroughHide the walkthrough

Given

Find

The energy of a photon is enough to remove an electron from a hydrogen atom.

Answer

The theory behind these problems

Work through the topic if a problem will not give in.

Photons and the photoelectric effectPhoton energy and momentum, photoelectric effect equation and red boundary.

Formulas by topic

Look up symbols and units of measurement in the reference.

WorkA · J Frequencyν · Hz EnergyE, W · J