Chapter 4: Problem 71

Describe few sources of light briefly.

Short Answer

Expert verified

Question: Identify and briefly describe five sources of light, including both artificial and natural sources. Answer: Five sources of light include: 1. Sun: A major natural source of light, the sun emits light due to nuclear fusion reactions happening at its core, providing energy for life on Earth. 2. Incandescent light bulb: An artificial source of light, it functions by passing an electric current through a thin metal filament which gets heated and emits light, though inefficiently. 3. Fluorescent lamp: An energy-efficient artificial light source where a glass tube with mercury vapor emits ultraviolet light, which gets converted to visible light by a phosphor coating. 4. Light Emitting Diode (LED): A highly energy-efficient and durable artificial light source, LEDs pass an electric current through a semiconductor, emitting photons of light, and are widely used in various applications. 5. Fire: A natural source of light achieved through combustion, examples of fire-based light sources include campfires and candles for natural sources, and gas stoves and lighters for artificial sources.

Step by step solution

1. Sun (Natural source)

The sun is a major natural source of light for our planet. It is a giant ball of gas that emits light and heat due to nuclear fusion reactions happening at its core. This produced light reaches Earth and provides the energy needed to sustain life, enabling vision during the daytime and affecting our daily routines and sleep patterns.

2. Incandescent light bulb (Artificial source)

Incandescent light bulbs are a common source of artificial light. They function by passing an electric current through a thin metal filament, usually made of tungsten. As the current flows through the filament, it gets heated and starts to emit light. These bulbs are not very efficient, as a majority of the input energy is wasted as heat, with only a small percentage being converted to visible light.

3. Fluorescent lamp (Artificial source)

Fluorescent lamps are another form of artificial light widely used in homes and offices. They consist of a glass tube filled with low-pressure mercury vapor and a phosphor coating on the interior surface. When an electric current is passed through the tube, the mercury vapor emits ultraviolet (UV) light. This UV light then hits the phosphor coating, which absorbs the energy and converts it to visible light. Fluorescent lamps are more energy-efficient than incandescent bulbs.

4. Light Emitting Diode (LED) (Artificial source)

LEDs are a highly energy-efficient and durable source of artificial light. They function by passing an electric current through a semiconductor, which then emits photons (particles of light). LEDs come in a wide range of colors and applications, from general illumination to traffic signals and electronic displays, and are becoming a popular choice for both residential and commercial lighting.

5. Fire (Natural source)

Fire is a natural source of light, used by humans for thousands of years. When a substance is burnt, it undergoes a chemical reaction called combustion. During combustion, the fuel reacts with oxygen to produce heat and light. Examples of natural fire-based light sources include campfires and candles, while artificial sources involve gas stoves and lighters.

Unlock Step-by-Step Solutions & Ace Your Exams!

Full Textbook Solutions
Get detailed explanations and key concepts
Unlimited Al creation
Al flashcards, explanations, exams and more...
Ads-free access
To over 500 millions flashcards
Money-back guarantee
We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Natural and Artificial Light

Understanding the distinction between natural and artificial sources of light is essential in comprehending how we illuminate our world. Natural light refers to light that comes from natural sources, with the sun being the primary provider. It floods our planet with the energy necessary for life, influencing natural cycles and human activities. On the other side, artificial light is created through technological means to supplement natural light or provide illumination where and when the sun's light is unavailable. This can range from the warm glow of a campfire, which has served as an age-old source of light and warmth, to various electrically powered devices that have become standard in the modern world.

In education, understanding these concepts can shed light on how different sources affect energy consumption, environmental impact, and the quality of light provided. From enhancing mood to improving visibility, both natural and artificial lighting play crucial roles in our daily lives.

Incandescent Light Bulb

The incandescent light bulb is one of the oldest electrical lighting technologies still in use. It operates on a simple principle: an electric current is passed through a resistive filament, typically made of tungsten, which then heats up to a high temperature until it glows and emits light.

Despite its widespread use for decades, the incandescent bulb is not very energy-efficient. Most of its energy use results in heat rather than visible light, making it a less ideal option in terms of energy conservation. However, its ability to provide a warm, ambient glow has kept it popular in many households, especially where color rendering and atmosphere are more important than energy efficiency.

Fluorescent Lamp

The fluorescent lamp is a more complex light source, designed to overcome some of the inefficiencies of the incandescent bulb. It consists of a glass tube filled with mercury vapor. When an electrical current flows through the vapor, it causes the emission of ultraviolet (UV) light. This UV light then stimulates a phosphor coating on the inside of the tube, which fluoresces and emits visible light.

Fluorescent lamps are more energy-efficient than incandescent bulbs, as they convert a higher proportion of electric energy into visible light. They also last longer, making them a cost-effective option for various settings. Nonetheless, they have some drawbacks, such as containing mercury, which is harmful to the environment if not disposed of properly, and sometimes producing a less natural quality of light.

LED Lighting

Among the most significant advances in lighting technology is the development of LED (Light Emitting Diode) lighting. LEDs function by passing an electric current through a semi-conductor material, which emits photons—basic particles of light. This process is highly energy-efficient, translating to lower energy costs and a reduced environmental footprint.

LED lighting is known for its long lifespan, durability, and the ability to produce a wide spectrum of colors. They have revolutionized the lighting industry, finding applications in residential, commercial, and industrial settings, as well as in electronic devices and signals. With the potential for integration into smart home systems and their minimal energy consumption, LEDs represent the cutting edge of sustainable lighting solutions.

Describe few sources of light briefly.

Short Answer

Step by step solution

1. Sun (Natural source)

2. Incandescent light bulb (Artificial source)

3. Fluorescent lamp (Artificial source)

4. Light Emitting Diode (LED) (Artificial source)

5. Fire (Natural source)

Key Concepts

Natural and Artificial Light

Incandescent Light Bulb

Fluorescent Lamp

LED Lighting

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Physics Textbooks

Fields in Physics

Wave Optics

Electricity and Magnetism

Oscillations

Conservation of Energy and Momentum

Energy Physics

Study anywhere. Anytime. Across all devices.