Question

Which kind of lamp, incandescent or fluorescent, is more efficient? 1\. Incandescent lamps, because they release all of the radiation they originally produce 2\. Fluorescent lamps, because they produce only radiation in the visible range 3\. Incandescent lamps, because no energy is lost in the conversion of energy from one wavelength to another 4\. Fluorescent lamps, because they multiply the intensity of radiation as it is converted from ultraviolet to visible light

Short answer

Fluorescent lamps are more efficient because they produce only radiation in the visible range.

Step-by-step solution

Incandescent lamps produce light by heating a filament (usually made of tungsten) until it becomes hot enough to emit visible light. The majority of energy consumed by incandescent lamps is actually converted into heat, not light, making them relatively inefficient. #Step 2: Understanding Fluorescent Lamps#

Fluorescent lamps, on the other hand, generate light by passing an electrical current through a low-pressure gas (such as mercury vapor) inside the lamp. This causes the gas to emit ultraviolet (UV) radiation, which is then converted into visible light by a phosphorescent coating on the inside surface of the lamp. Fluorescent lamps are generally more energy-efficient than incandescent lamps because they convert a higher percentage of the consumed electrical energy into visible light. #Step 3: Comparing the Factors of Efficiency#

Based on our understanding of incandescent and fluorescent lamps, we can now compare the given statements and determine which type of lamp is more efficient: 1. Incandescent lamps release all of the radiation they produce, but much of this radiation is in the form of heat, not light. This makes them less efficient. 2. Fluorescent lamps produce only radiation in the visible range, indicating higher efficiency. 3. Incandescent lamps do not lose energy in the conversion from one wavelength to another. However, the majority of the energy is still wasted as heat, so they are less efficient. 4. Fluorescent lamps convert ultraviolet radiation into visible light, but they do not "multiply" the intensity of radiation. However, this conversion process is more efficient than the release of heat by incandescent lamps. #Step 4: Choosing the Correct Option#

Based on our comparison in Step 3, we can now conclude that the correct answer is: \(2\). Fluorescent lamps are more efficient because they produce only radiation in the visible range.

Key concepts

Incandescent vs Fluorescent Lamps

Understanding the difference between incandescent and fluorescent lamps is essential when discussing efficiency. Incandescent lamps work on the principle of incandescence: they produce light by heating a filament until it glows. The heat produced is an indication of energy not being used for light, thus revealing inefficiency.

Fluorescent lamps, alternatively, use a different approach. They generate light through fluorescence - a process where ultraviolet light is emitted by gas inside the lamp, and then a phosphor coating inside the lamp transforms it into visible light. This process is generally more efficient as less energy is lost as heat. Therefore, while incandescent lamps have the advantage of simplicity, fluorescent lamps outshine them in terms of energy efficiency.

Energy Efficiency

The measure of how well a device converts input energy into useful output is called energy efficiency. When we scrutinize light bulbs, this translates to the amount of electrical energy converted into visible light, as opposed to heat or other forms of non-useful energy.

Incandescent lamps have energy efficiencies of about 10%, meaning a considerable portion of the energy consumed is lost. Fluorescent lamps, however, can achieve efficiencies up to 25% or even greater. This higher efficiency rate not only makes fluorescent lamps more cost-effective in the long run but also more environmentally friendly by reducing wasted energy and the demand on power plants.

Visible Light Radiation

Visible light radiation is the portion of the electromagnetic spectrum that is visible to the human eye, which spans from about 380 to 750 nanometers in wavelength. Incandescent bulbs emit light across a wide spectrum, including non-visible infrared, which is felt as heat, illustrating their inefficiency in light production.

Fluorescent lamps, in contrast, are designed to emit a higher proportion of their energy within the visible spectrum. This trait enhances their practicality for lighting purposes, since producing light outside of the visible range serves no beneficial purpose in most lighting applications and constitutes an energy loss.

Wavelength Conversion

The concept of wavelength conversion is pivotal to the operation of fluorescent lamps. These lamps convert the shorter wavelengths of ultraviolet (UV) radiation into longer wavelengths in the visible spectrum. This is accomplished via a phosphor coating inside the lamp. The UV radiation excites the phosphors, causing them to glow – a direct conversion of energy into visible light.

The misconception that fluorescent lamps 'multiply' light is incorrect. Instead, they efficiently transform one type of light into another more useful form. It is this conversion efficiency, rather than multiplication, that makes fluorescent lamps more efficient than incandescent lamps, which do not undergo any wavelength conversion and emit most of their energy as heat.