Electroluminescence: Light Emission via Electrical Energy

The question asks for the specific term that describes the process of emitting light when an electrical source of energy is applied. Let's analyze the options to find the correct match.

Understanding Light Emission Processes

Several phenomena involve the emission of light. It's important to differentiate them based on the energy source that triggers the light emission:

• Photoluminescence: This process involves materials absorbing photons (light energy) and then re-emitting light. The initial energy source is light itself. Examples include fluorescence and phosphorescence.
• Electroluminescence: This is the phenomenon where a material emits light directly in response to the passage of an electric current or the application of an electric field. This perfectly matches the description given in the question – using an electrical source to produce light. Common examples include Light Emitting Diodes (LEDs) and Organic Light Emitting Diodes (OLEDs).
• Transconductance: This term belongs to electronics and describes the ratio of the change in output current to a change in input voltage for a device, like a transistor. It is unrelated to light emission.
• Trans luminescence: This is not a standard scientific term commonly used to describe light emission processes in physics or chemistry. It seems like a distractor term.

Defining Electroluminescence

Electroluminescence is the optical and quantum mechanical phenomenon where a material emits light (or visible radiation) in reaction to an electric current passing through it, or when subjected to a strong electric field. This occurs because the electric field or current energizes charge carriers (electrons and holes) within the material, which then recombine, releasing energy in the form of photons (light).

Calculation/Mechanism (Conceptual):

While no specific calculation is needed for this question, the basic principle involves:

1. Applying an electric field or current to a suitable material (often a semiconductor).
2. Energizing charge carriers within the material.
3. Recombination of these charge carriers (e.g., an electron falling into a hole).
4. Release of energy during recombination, often in the form of a photon. The energy of the photon ($E_{photon}$) is related to the material's band gap ($E_g$) or the energy levels involved, roughly $E_{photon} \approx E_g$.

Conclusion

Based on the definitions, the process of giving off light by applying an electrical source of energy is specifically called electroluminescence.