Photoelectric Effect and Quantum Theory

The video explores the photoelectric effect, highlighting that frequency, not intensity, determines whether electrons are emitted from a metal surface. The wave model fails to explain this phenomenon, as it suggests energy absorption is gradual. In contrast, the quantum model, which views light as photons, explains that electrons absorb energy instantaneously. This model accounts for experimental observations, such as the lack of time delay and the increase in kinetic energy with higher frequency light.

Why does ultraviolet light cause the photoelectric effect on zinc, but visible light does not?

• Ultraviolet light has a higher intensity.

• Ultraviolet light has a higher frequency.

• Visible light has more energy.

• Visible light is absorbed by zinc.

According to the wave model, what determines the energy absorbed by an electron?

• The frequency of the light.

• The intensity of the light.

• The type of metal.

• The color of the light.

In the quantum model, what is light composed of?

• Atoms

• Electrons

• Photons

• Waves

What happens when an electron absorbs a photon with insufficient energy?

• The electron escapes the metal.

• The electron splits into smaller particles.

• The electron gains energy gradually.

• The electron remains trapped and releases energy.

What determines the energy of a photon?

• Its frequency

• Its color

• Its speed

• Its intensity

Why does increasing the intensity of light not increase the energy of emitted electrons?

• Intensity alters the type of metal.

• Intensity changes the frequency of light.

• Intensity affects the number of photons, not their energy.

• Intensity increases the speed of electrons.

How does increasing the frequency of light affect the emitted electrons?

• It decreases their energy.

• It increases their energy.

• It changes their direction.

• It reduces their number.

What is the effect of shining dim light above the threshold frequency on a metal surface?

• The metal heats up.

• Electrons are emitted slowly.

• Photoelectric effect occurs instantly.

• No photoelectric effect occurs.

According to the quantum model, how is energy transferred to an electron?

• Gradually over time

• Instantly in discrete packets

• Through continuous waves

• By increasing intensity

What does the quantum model explain about the photoelectric effect that the wave model cannot?

• The role of light intensity

• The instantaneous nature of electron emission

• The type of metal used

• The color of emitted light