Experimental Investigation Of Black Body Using Various Diameter Of Bore On Different Metallic Dimension

ABSTRACT

The development of a satisfacotry description of the radiation emitted from an ideal “Black Body” was a fundamental step in Modern Physics, and the result plays important roles in Astronomy, Cosmology, and technology to this day. With the classical electrodynamics suited to the universe in focus and recurring to the hyperspherical coordinates, it is shown that the spectral energy density as well as the total energy density are sensible to the dimensionality of the universe. Wien’s displacement law and the Stefan-Boltzmann law are properly generalized. Nevertheless, even in the absence of detailed quantitative agreement with this ideal spectrum, the tungsten filament from a projector bulb can be used to confirm the fundamental physics contained in Planck’s formula, and to determine the a particular combination of three fundamental physical constants (hc/kB ). In this experiment you will determine this ratio, and explore some of the systematic effects that cause measured spectra to deviate from the ideal behavior

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

• INTRODUCTION
• BACKGROUND OF THE STUDY
• OBJECTIVE OF THE STUDY
• SCOPE OF THE STUDY
• BLACK BODY RADIATION SOURCES
• SELECTING A BLACK BODY RADIATION SOURCE
• APPLICATIONS OF BLACK BODIES

CHAPTER TWO

LITERATURE REVIEW

• DEFINITION OF A BLASK BODY
• RADIATION BY HOT BODIES
• OVERVIEW OF BLACK-BODY RADIATION
• THEORY BLACK-BODY RADIATION
• REVIEW OF BLACK BODY
• RESEARCH EQUATIONS
• HISTORICAL BACKGROUND OF THE STUDY

CHAPTER THREE

METHODOLOGY

• INTRODUCTION
• EXPERIMENTAL APPARATUS
• EXPERIMENTAL PROCEDURE

CHAPTER FOUR

4.0      RESULT ANALYSIS

• RESULTS

CHAPTER FIVE

• CONCLUSION
• REFERENCES

CHAPTER ONE

1.0                                          INTRODUCTION

1.1                                  BACKGROUND OF THE STUDY

All bodies emit electromagnetic radiation over a range of wavelengths. In an earlier chapter, we learned that a cooler body radiates less energy than a warmer body. We also know by observation that when a body is heated and its temperature rises, the perceived wavelength of its emitted radiation changes from infrared to red, and then from red to orange, and so forth. As its temperature rises, the body glows with the colors corresponding to ever-smaller wavelengths of the electromagnetic spectrum. This is the underlying principle of the incandescent light bulb: A hot metal filament glows red, and when heating continues, its glow eventually covers the entire visible portion of the electromagnetic spectrum. The temperature (T) of the object that emits radiation, or the emitter, determines the wavelength at which the radiated energy is at its maximum. For example, the Sun, whose surface temperature is in the range between 5000 K and 6000 K, radiates most strongly in a range of wavelengths about 560 nm in the visible part of the electromagnetic spectrum. Your body, when at its normal temperature of about 300 K, radiates most strongly in the infrared part of the spectrum.

Radiation that is incident on an object is partially absorbed and partially reflected. At thermodynamic equilibrium, the rate at which an object absorbs radiation is the same as the rate at which it emits it. Therefore, a good absorber of radiation (any object that absorbs radiation) is also a good emitter. A perfect absorber absorbs all electromagnetic radiation incident on it; such an object is called a blackbody.

Although the blackbody is an idealization, because no physical object absorbs 100% of incident radiation, we can construct a close realization of a blackbody in the form of a small hole in the wall of a sealed enclosure known as a cavity radiator. The inside walls of a cavity radiator are rough and blackened so that any radiation that enters through a tiny hole in the cavity wall becomes trapped inside the cavity. At thermodynamic equilibrium (at temperature T), the cavity walls absorb exactly as much radiation as they emit. Furthermore, inside the cavity, the radiation entering the hole is balanced by the radiation leaving it. The emission spectrum of a blackbody can be obtained by analyzing the light radiating from the hole. Electromagnetic waves emitted by a blackbody are called blackbody radiation.

1.2                              OBJECTIVES OF THE STUDY

At the end of this study students involved shall be able to study the following:

1. The black-body model, which is of primary importance in thermal radiation theory and practice.
2. The fundamental laws of radiation of such a

• Natural and artificial physical objects, which are close in their characteristics to black bodies, are considered

1. The quantitative black-body radiation laws and their corollaries are analysed in
2. The notions of emissivity and absorptivity of physical bodies of grey-body radiation character are also
3. The HirchhoRlaw, its various forms and corollaries are analysed on this

1.3                                    SCOPE OF THE STUDY

Black body radiation is the emission of electromagnetic energy by an object which is in a thermodynamic equilibrium. The blackbody emits an amount of energy depends on its temperature, with ideal blackbody absorbing and re-emitting all the incident radiations it receives at any wavelength.

The blackbody radiation is a common phenomenon, observed when the temperature of an object increases. The electromagnetic radiation occupies a wide spectrum, both in the visible and invisible regions depending on the temperature of the object and amount of radiation.

1.4                       BLACK BODY RADIATION SOURCES

All objects are black body radiators, the amount of radiation and position in the spectrum depends on the object temperature as well its emissivity. Some examples of blackbody radiators that emit visible light or whose radiation is used for other processes include the electric heaters, incandescent light bulbs, stoves, the sun, the stars, night vision equipment, burglar alarms, warm-blooded animals, etc.

Typical blackbody radiations:

• A filament bulb converts the electrical energy into light energy, at switch on or switch off, when the filament is not fully heated or cooling down, it radiates energy in the infrared regions, initially, and goes to red, then yellow until it reaches an almost white light when fully energized.
• As the welding temperature of a piece of metal increases, it initially glows red, then orange, and the color continues changing until it becomes a bright, bluish cast. The glow at very high temperatures is very intense and painful to look at using the naked eyes. Due to this, welders usually use dark goggles to prevent damage to their eyes.

An object that is not very hot still emits radiation, but in the infrared region. This is utilized in night vision equipment which is used to detect the infrared radiation and convert this into a visible image. This allows the detection of warm-blooded animals and people at night.

The black body radiation from animals is usually in the infrared radiation, and cannot be seen with the naked eye; however, a thermal camera can be used to see the thermal radiation from an animal. The image appears as a glowing object due to the black body radiation, unlike during the day when the person reflects the light falling on them.

The hot and warmer objects emit more energetic radiation and cool faster than the cooler objects. In the absence of a heat source, the objects will eventually reach the same temperature as the surroundings and are said to be in thermal equilibrium.

1.5          SELECTING A BLACK BODY RADIATION SOURCE

The blackbody radiators for commercial applications almost approach an ideal blackbody and are used for a variety of applications. The choice of the blackbody radiation sources depends on the temperature, type of the application and environment. The major factors considered include;

• Temperature
• Emissivity
• Size of Emissive area
• Warm-up time
• Cooling time
• Regulation stability

The temperature depends on the object under test. For example, a low-temperature blackbody is suitable for applications such as calibrating IR sensor that looks at buildings, vehicles, or human bodies.

The blackbody radiation sources are available in three main categories, based on the temperature range.

• Low-temperature blackbody with a range of between -40 °C to +150 °C
• High temperature extended area blackbody – from ambient temperature up to +600 °C
• High-temperature cavity blackbody – from ambient temperature up to 1200 °C

1.6                        APPLICATIONS OF BLACK BODIES

The blackbodies are used for lighting, heating, security, thermal imaging, as well as testing and measurement applications.

Since the intensity of the energy at any temperature and wavelength and can be determined using the Planck Law of radiation. A blackbody radiation source with a known temperature, or, whose temperature can be measured, is usually used for calibrating and testing the radiation thermometers.