Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

Luminous EfficacyLuminous efficacy is the amount of luminous flux in lumens that a particular lamp gives per unit consumption of electric power. The unit of luminous efficacy is in lumens/watt. Luminous efficacy is the measure of the energy efficiency of a lamp – and it varies based on the type of lamp.The luminous efficiency of the incandescent lamp is around 10 – 20 lumens/watt whereas a fluorescent lamp is around 60 – 100 lumens/watt. This difference is due to fluorescent lamps being more ene

What is Transmittance?The transmittance of a surface or material is defined as the part of the light that moves through the other side of the surface. When light passes through any surface or material, it can be transmitted, reflected, or absorbed. Transmittance and reflectance are closely related concepts.Transmittance is defined as a ratio of the intensity of incident light (I0) to the amount of intensity passes through the object (I). The transmittance is denoted as T.As shown in the above fi

What is ReflectanceReflectance is defined as the ratio of the radiant flux reflected from the surface or body of a material (фr) to the incident radiant flux (фi). Reflectance is denoted by ρ (or p).The reflectance is a ratio of radiant flux. Therefore, it is unitless. The reflectance varies as per the wavelength distribution of the incident radiation. Reflectance and transmittance are closely related concepts.Reflectance can be categorized into two types. One is specular reflectance (ρs) and th

What is Radiometry?Radiometry is a technique to measure electromagnetic radiation for any wavelength. Photometry is similar to radiometry, but photometry is related to visible light signals only, while radiometry includes signals of any wavelength – like ultraviolet, infrared, and visible light.Radiometry is a method of detecting the radiation of material body and substance. According to Planck’s law, all material and substance radiate energy in the form of electromagnetic waves. Radiometry is u

What are the Fresnel Equations?The Fresnel Equations (also known as the Fresnel coefficients) are defined as the ratio of the electric field of a reflected and transmitted wave to the electric field of the incident wave. This ratio is complex and hence, it describes relative amplitude as well as phase shifts between the waves.The Fresnel Equations (Fresnel coefficients) describe the reflection and transmission of light when it is incident on an interface between two different mediums. The Fresne

What is Stroboscopic Motion?Stroboscopic motion (also known as the Stroboscopic Effect) is defined as a visual phenomenon that occurs when continuous rotational motion is represented by a series of short samples (as opposed to a continuous view) at a sampling rate close to the period of the motion.An example of stroboscopic motion is the wheel of a car. When a car is running forward, it seems like the wheel of a car is moving backward if you observe the wheel in film. Stroboscopic Motion Example

Radiant flux is a term that describes the amount of radiant energy that is emitted, reflected, transmitted, or received by an object per unit of time. Radiant energy is the energy carried by electromagnetic waves, such as light, radio waves, microwaves, infrared, ultraviolet, and X-rays. Radiant flux is also known as radiant power or optical power (in the case of light).Radiant flux is an important concept in radiometry, which is the science of measuring and analyzing electromagnetic radiation.

A black body is defined as an idealized object that absorbs all electromagnetic radiation that falls on it and emits radiation with a continuous spectrum that depends only on its temperature. Black body radiation is the thermal radiation emitted by a black body in thermodynamic equilibrium with its surroundings. Black body radiation has many applications in physics, astronomy, engineering, and other fields.What is a Black Body?A black body is a theoretical concept that represents an ideal absorb

Photometry is the science of measuring light in terms of its perceived brightness to the human eye. It is different from radiometry, which measures radiant energy (including light) in terms of absolute power. Photometry only considers the visible range of wavelengths (light) that can stimulate the human eye.The human eye can detect radiation that has a wavelength between 370 nm and 780 nm. This range is called the visible spectrum or simply light. Radiation with a wavelength shorter than light i