Question

Match the device with its definition. $$\begin{array}{|l|}\hline \text { 1. A device which converts electromagnetic } \\ \text { (often optical) energy directly to electricity } \\\\\hline \text { 2. A device made from diodes of two } \\\\\text { dissimilar materials which converts a } \\\\\text { temperature differential to electricity } \\ \hline \text { 3. A device which converts chemical energy } \\ \text { to electrical energy through the oxidation of } \\ \text { a fuel } \\\\\hline \text { 4. A device which converts mechanical stress } \\\\\text { directly to electricity } \\\\\hline \text { 5. A device made from a crystal without a } \\\\\text { center of symmetry which converts a } \\\\\text { temperature differential to electricity } \\\\\hline\end{array}$$ $$\begin{array}{|l|}\hline \text { A. } \\\\\text { Fuel Cell } \\\\\hline \text { B. } \\\\\text { Photovoltaic } \\ \text { Device } \\\\\hline \text { C. } \\\\\text { Piezoelectric } \\\\\text { Device } \\ \hline \text { D. } \\\\\text { Pyroelectric } \\\\\text { Device } \\\\\hline \text { E. Thermo- } \\\\\text { electric } \\\\\text { Device }\\\\\hline\end{array}$$

Short answer

1-B, 2-E, 3-A, 4-C, 5-D

Step-by-step solution

Analyze Description of Device 1

The description is 'A device which converts electromagnetic (often optical) energy directly to electricity.' This matches with device B, which is a 'Photovoltaic Device.' Photovoltaic devices, such as solar panels, convert light (a form of electromagnetic energy) into electricity.

Analyze Description of Device 2

The description is 'A device made from diodes of two dissimilar materials which converts a temperature differential to electricity.' This matches with device E, which is a 'Thermoelectric Device.' Thermoelectric devices use materials with different electrical properties to convert temperature differences into electric power.

Analyze Description of Device 3

The description is 'A device which converts chemical energy to electrical energy through the oxidation of a fuel.' This matches with device A, which is a 'Fuel Cell.' Fuel cells generate electricity through a chemical reaction, usually involving hydrogen and oxygen.

Analyze Description of Device 4

The description is 'A device which converts mechanical stress directly to electricity.' This matches with device C, which is a 'Piezoelectric Device.' Piezoelectric devices generate electric charge in response to applied mechanical stress.

Analyze Description of Device 5

The description is 'A device made from a crystal without a center of symmetry which converts a temperature differential to electricity.' This matches with device D, which is a 'Pyroelectric Device.' Pyroelectric devices use certain types of crystals to generate a temporary voltage when they are heated or cooled.

Key concepts

Photovoltaic Devices

Photovoltaic devices are fascinating pieces of technology that allow us to harness the power of the sun. At their core, these devices convert light into electrical energy, making them an integral component of renewable energy solutions. Photovoltaic devices, colloquially referred to as solar panels, operate based on the photovoltaic effect, which was discovered by physicist Alexandre-Edmond Becquerel in 1839.

• When sunlight strikes the surface of a solar cell, it excites electrons, creating electron-hole pairs.
• This movement of electrons generates a flow of electric current, which can be harnessed for energy use.

Modern solar panels are made up of several layers, often using silicon as a semiconductor. By understanding the basic principles of photovoltaics, we can appreciate the potential of solar energy in powering a sustainable future.

Thermoelectric Devices

Thermoelectric devices have the ability to convert temperature differences directly into electrical voltage. Known for their simplicity and reliability, these devices utilize a mechanism called the Seebeck effect to generate electricity.

• The Seebeck effect occurs when two different metals are joined at two junctions, and a temperature gradient is applied.
• Electrons flow from the hot side to the cold side, creating an electric current.

Unlike other types of energy conversion devices, thermoelectric devices function without moving parts, reducing the risk of mechanical failure. Their application can be seen in power generation from waste heat or precise temperature control in electronic devices, making them valuable in both industrial and personal settings.

Fuel Cells

Fuel cells are unique in their conversion of chemical energy directly into electricity through a chemical reaction. They do this by combining hydrogen with oxygen in what's known as an electrochemical reaction. This reaction is highly efficient and clean, as the only byproduct is water, making fuel cells an eco-friendly alternative to fossil fuels.

• A typical fuel cell consists of two electrodes where reactions occur (anode for fuel, cathode for oxidant).
• An electrolyte separates the electrodes, allowing ions to move but not electrons, creating a current.
• Fuel cells are flexible, scalable, and can be used in various applications from powering cars to providing backup energy in buildings.

By utilizing hydrogen, the most abundant element in the universe, fuel cells represent a promising step toward a sustainable energy landscape.

Piezoelectric Devices

Piezoelectric devices are intriguing technology that convert mechanical stress into electrical energy. This property is known as piezoelectricity, a phenomenon discovered in the 19th century.

• Certain materials, like quartz and barium titanate, generate an electric charge when mechanically deformed.
• The piezoelectric effect can be used in various applications, including sensors, actuators, and even as energy harvesters in wearable technologies.

The versatility and responsiveness of piezoelectric materials extend their utility across multiple industries, helping to integrate smart technology into everyday life. Whether in medical devices or in creating innovative wearable tech, piezoelectric materials offer enduring solutions powered by the energy of movement.

Pyroelectric Devices

Pyroelectric devices leverage temperature changes to generate electrical energy. These devices are based on pyroelectricity, which is a property of certain crystalline materials.

• When these crystals experience a change in temperature, they generate a temporary voltage.
• This is due to the alignment of the electrical dipoles within the crystal structure.

Pyroelectric devices are often used in infrared sensors, motion detectors, and some types of cameras. The key advantage of pyroelectric devices is their ability to accurately detect and respond to changes in temperature without direct contact. This makes them especially useful in non-invasive sensing technologies, expanding possibilities in security, scientific research, and consumer electronics.