Physics Chapter: Quantum and Photoelectric Effect

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What concept does Planck's quantum hypothesis primarily explain?

The emission of light by glowing lightbulbs (correct)

The interference of light waves

The diffraction patterns of light

The behavior of electromagnetic waves

Which phenomenon is associated with Maxwell's electromagnetic wave theory?

Radioactive decay

Thermal conduction

Chemical reactions

Interference and diffraction (correct)

At what condition does a blackbody begin to emit visible light?

At room temperature

In a vacuum

When exposed to radiation

When heated (correct)

What relationship does the document suggest exists between temperature and emitted light?

Higher temperature increases the amount of emitted light Signup and view all the answers

Which of the following is a potential query left unanswered in the discussion?

How does a glowing lightbulb emit light? Signup and view all the answers

What is the primary effect observed when electromagnetic radiation strikes the cathode in a photocell?

Electric current is generated immediately. Signup and view all the answers

Which statement best describes the energy transfer during the photoelectric effect?

Energy is transferred in discrete or quantized amounts. Signup and view all the answers

What happens when no electromagnetic radiation is incident on the cathode of a photocell?

No current is observed in the ammeter. Signup and view all the answers

What role does the low voltage from the DC power source in a photocell serve?

To prevent the spontaneous emission of electrons from the cathode. Signup and view all the answers

Which observation indicates the nature of light in the context of the photoelectric effect?

Light exhibits no wave nature in the process. Signup and view all the answers

What happens when electromagnetic radiation is below the threshold frequency?

No current is produced regardless of light intensity. Signup and view all the answers

Which statement reflects the relationship between frequency and the speed of emitted electrons?

Higher frequency above the threshold increases the speed of emitted electrons. Signup and view all the answers

Why could Maxwell's wave theory not explain the photoelectric effect?

It claimed that intensity affects electron emission energy. Signup and view all the answers

What characterizes the threshold frequency for different metals?

It is specific to each metal and depends on its properties. Signup and view all the answers

What concept did Einstein introduce to explain the photoelectric effect?

Light consists of discrete packets of energy called photons. Signup and view all the answers

What represents the relationship between the photon energy and the kinetic energy of the emitted photoelectron?

$E_{photon} = E_k + E_{ext}$ Signup and view all the answers

Which statement accurately describes the effect of brightness on current in photoelectric emission?

Brightness increases current if $f < f_0$ Signup and view all the answers

What is the correct expression for the maximum kinetic energy of the emitted photoelectron?

$E_{k_{max}} = hf - W$ Signup and view all the answers

What occurs when a photon interacts with an electron on a cathode in photoelectric effect?

The electron can accumulate energy to eventually leave Signup and view all the answers

Which of the following correctly describes the conditions necessary for photoelectrons to be emitted from a metal surface?

The incoming light must exceed a certain photon energy corresponding to frequency $f_0$ Signup and view all the answers

What does the maximum kinetic energy ($E_{max}$) of a photoelectron depend on?

The energy of the photon minus the work function Signup and view all the answers

What happens when the voltage of the battery in the photoelectric cell is increased sufficiently?

Electron repulsion becomes too strong for movement Signup and view all the answers

Which component of the photoelectric effect does the work function ($W$) represent?

The minimum energy needed to release an electron from the surface Signup and view all the answers

Based on the graph of the photoelectric effect, how does the maximum kinetic energy of photoelectrons change with frequency?

It increases linearly with increasing frequency Signup and view all the answers

What is the formula to calculate the maximum kinetic energy ($E_{max}$) of a photoelectron?

$E_{max} = E_{photon} - W$ Signup and view all the answers

What did Einstein propose about photons in 1916?

Photons can have momentum. Signup and view all the answers

What evidence did Arthur Compton provide in 1922?

That scattered x-rays exhibit changes in wavelength. Signup and view all the answers

Which equation relates to kinetic energy in the context of the Compton effect?

$E_k = rac{1}{2} mv^2$ Signup and view all the answers

What does the slope of the graph related to the Compton effect represent?

Planck's constant. Signup and view all the answers

Which of the following statements about photons is NOT correct based on the Compton effect?

Photons possess mass. Signup and view all the answers

What occurs to a photon when it interacts with an electron during the Compton effect?

It loses energy and transfers momentum to the electron. Signup and view all the answers

Which statement accurately summarizes the Compton effect's demonstration of light properties?

Light can scatter and transfer momentum, indicating particle-like behavior. Signup and view all the answers

In the context of the Compton effect, what happens to photons that are not scattered?

They remain unscattered and pass through the target material. Signup and view all the answers

What role does the target material play in the Compton effect?

It allows some photons to pass through unscattered and interacts with others. Signup and view all the answers

During the scattering process in the Compton effect, what happens to a photon in terms of its energy?

It loses energy when interacting with electrons. Signup and view all the answers

What is the energy of a single photon emitted by a handheld laser with a wavelength of 630 nm?

3.166 x 10^-19 J Signup and view all the answers

In electron volts, what is the energy of a photon emitted by a handheld laser with a wavelength of 630 nm?

1.97 eV Signup and view all the answers

How many photons are emitted by a handheld laser with 100 mW power over 25 seconds?

7.96 x 10^16 Signup and view all the answers

Who discovered the photoelectric effect and which device did he use?

J.J. Thomson; cathode ray tube Signup and view all the answers

What is a necessary condition for the photoelectric effect to occur?

Sufficiently high voltage Signup and view all the answers

What does Planck's constant represent in the equation $E = h u$?

A proportionality factor for quantized energy Signup and view all the answers

How does Einstein's quantum theory differ from Planck's theory?

Einstein applied quantization to light rather than just to atoms. Signup and view all the answers

In the equation $E = h f$, what does the variable f represent?

The frequency of the light Signup and view all the answers

What is the significance of the equation $c = f au$ in relation to electromagnetic radiation?

It demonstrates the relationship between speed, frequency, and wavelength. Signup and view all the answers

Which equation expresses the energy of a photon in relation to its wavelength?

$E = rac{hc}{ au}$ Signup and view all the answers

What was the primary issue with classical physics in explaining blackbody radiation?

It failed to account for energy distribution at higher frequencies. Signup and view all the answers

What does Planck's curve illustrate in the study of blackbody radiation?

The prediction of emitted intensity across different frequencies at a certain temperature. Signup and view all the answers

What resolution did Planck provide to the mismatch between classic theory and observed data of blackbody radiation?

Introduced the concept of quantized energy levels. Signup and view all the answers

How does the intensity of emitted radiation change as an object increases in temperature?

It shifts to higher frequencies with greater intensity. Signup and view all the answers

What underlying concept did the UV catastrophe challenge in classical physics?

The belief that all objects radiate energy in excess as temperature rises. Signup and view all the answers