What does “stimulated emission of radiation” mean?
Gas particles in a laser emit photons of light when exposed to an electric current.
Gas particles in a laser emit coherent light when bombarded with X-rays.
Electromagnetic currents are produced by neon particles when they bump into helium particles.
Radioactive particles in a laser emit gamma rays of the same wavelength.
The correct answer is:
Gas particles in a laser emit coherent light when stimulated by a photon of the same energy and wavelength, a process known as stimulated emission of radiation.
"Stimulated emission of radiation" refers to the process in which particles in a laser (commonly gas particles or other materials) emit photons of light. However, this emission occurs in a specific manner that is different from ordinary or spontaneous emission of light.
It occurs when an incoming photon stimulates an excited particle to emit another photon of the same wavelength, phase, and direction as the incoming photon. This process is possible due to the specific properties of the laser medium and the way atoms or molecules interact with light.
Unlike spontaneous emission, where photons are emitted randomly and independently by excited particles, stimulated emission requires an external source of photons to trigger the emission. This characteristic is vital in the functioning of lasers, as it enables the creation of coherent and concentrated beams of light.
In summary, for stimulated emission to occur, particles in a laser are stimulated by incoming photons of the same wavelength, leading to the emission of additional photons with the same properties, resulting in the production of a coherent laser beam.
The correct answer is: Gas particles in a laser emit coherent light when bombarded with X-rays.
"Stimulated emission of radiation" refers to a process in which gas particles in a laser emit coherent light when they are stimulated or excited by an external source. In this case, the external source is X-rays. When the gas particles, typically in a laser medium, absorb energy from the X-rays, they get excited to higher energy levels. As these particles return to their lower energy levels, they release energy in the form of photons, or particles of light. The emitted photons are coherent, meaning they have the same frequency and are in phase with each other, resulting in a concentrated beam of light that can travel over long distances without spreading out strongly.
To arrive at the correct answer, we can eliminate the other options:
- The first option, "Gas particles in a laser emit photons of light when exposed to an electric current," refers to simple emission of light, not stimulated emission. Stimulated emission occurs when particles are excited by an external source and release coherent light as a result.
- The third option, "Electromagnetic currents are produced by neon particles when they bump into helium particles," does not accurately describe stimulated emission of radiation. Stimulated emission refers to the release of photons, not the production of electromagnetic currents due to particle collisions.
- The fourth option, "Radioactive particles in a laser emit gamma rays of the same wavelength," is not an accurate description of stimulated emission. Stimulated emission is not caused by radioactivity; instead, it occurs when particles are stimulated or excited by an external source.
Therefore, the second option, "Gas particles in a laser emit coherent light when bombarded with X-rays," is the correct description of stimulated emission of radiation.