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Spontaneous Emission in Physics

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Questions and Answers

What happens during spontaneous emission?

Emission occurs only under specific conditions.

The emitted photon is always in phase with the stimulating photon.

A photon is emitted without any external influence. (correct)

An excited atom emits multiple photons simultaneously.

What can be inferred about the photons emitted during stimulated emission?

They are always incoherent.

They are coherent and emitted in the same direction. (correct)

They are emitted in different directions.

They have different frequencies.

How does the lifetime of an atom in an excited state relate to spontaneous emission?

It is approximately 10^-8 seconds. (correct)

It is significantly longer than 10^-8 seconds.

It has no impact on emission.

It is indefinite until stimulated.

What characterizes the radiation from ordinary light sources?

Emissions from different atoms are random and incoherent. Signup and view all the answers

Which statement about the energy of the emitted photon during spontaneous emission is accurate?

It has energy equal to the difference between the two states. Signup and view all the answers

What is the effect of a stimulating photon in stimulated emission?

It triggers the emission of another photon of the same frequency. Signup and view all the answers

In the context of lasers, why is stimulated emission significant?

It generates coherent and monochromatic light. Signup and view all the answers

What is the primary state change associated with spontaneous emission?

From a higher energy state to a lower energy state. Signup and view all the answers

Which of the following is NOT a characteristic of spontaneous emission?

Involvement of an external photon. Signup and view all the answers

Study Notes

Spontaneous Emission

Emission of a photon occurs when a system transitions from a higher energy state to a lower energy state without external intervention.
The average lifetime of the atomic system in an excited state is approximately 10^-8 seconds.
After this lifespan, the system returns to a lower energy state by emitting a photon, with energy described by the formula hf = E2 - E1.
Light emitted from ordinary sources results from spontaneous emission, characterized by non-coherent radiation.
Spontaneous emission results in the radiation being emitted in random directions by different atoms.

Stimulated Emission

Stimulated emission occurs when a photon (stimulating photon) of the right frequency prompts an excited atomic system to return to its ground state.
Both the stimulating photon and the photon emitted during stimulated emission share identical frequency, phase, and polarization, making them coherent.
This process results in photons being emitted in the same direction, contributing to laser action.

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Description

This quiz explores the concept of spontaneous emission in atomic systems. It covers the process by which an excited atom releases a photon as it transitions to a lower energy state. Understand the significance of average lifetime and energy transitions in light emission.