Concept of Reflection

The idea that light travels in straight lines is uppermost, while its wave character and other physical aspects are disregarded. Since the laws of reflection and refraction corollaries of the wave nature. Sources of light, such as the sun, stars, and electric lamps can be seen when the light they produce reaches the eyes. However, most objects can only be seen when light is reflected off the surface of an object. An object that reflects no light appears to be black. On the other hand an object that reflects all of the light appears the same colour as the light source, for instance something which reflects all of the white light reaching it from the sun appears white light mirrors and highly polished surfaces, reflect light strongly and we shall now deal with the laws governing the reflection.

Definition of Science

 This section is to give you more information about science so you can know more about doing and understanding those things which make you ethical and prosperous. In the previous section, we saw that science is the word for human activity which produces being ethical and prosperous. This section is a more complete elaboration of the process of science. This section is provided because the more you know of the tool “science,” the better you can use it to accomplish your ends. This systematic elaboration of the process can be accomplished by way of elaborating the definition of science. Science is very much more complex than pat definitions which you can memorize and then put the issue away. The scientific method is what has evolved to help people tell the truth and to understand the world. The following definitions are attempts at applying words to what is done so that you can gain the knowledge through vicarious experience rather than actual experience (the hard way).

The velocity of a body moving with uniform speed may not be uniform.

 We know, velocity is a vector. It has both value and direction. So, change in direction or value will result in change of vector. So, if direction of an object going at uniform velocity changes, velocity will also change. Meaning, uniform speed does not always mean uniform velocity.

তাপ সঞ্চালন কাকে বলে?

তাপ সঞ্চালন কাকে বলে? তাপ বেশি তাপমাত্রার স্থান থেকে কম তাপমাত্রার স্থানে যেতে পারে। তাপের এই স্থান পরিবর্তনকে তাপ সঞ্চালন বলে। তাপ সঞ্চালনের প্রকারভেদ তাপ সঞ্চালন তিনভাবে হয়। যথা- পরিবহন পরিচলন ও বিকিরণ  

পল্লি সাহিত্য কাকে বলে?

পল্লি অঞ্চলকে কেন্দ্র করে তথা পল্লির বিভিন্ন উপাদান যেমন - মাটি, পুকুর, ডোবা, পাখি, পশু, মানুষ, পেশা প্রভৃতি সংশ্লিষ্ট সাহিত্যকে পল্লি সাহিত্য বলে।

ভবিষ্যত অনুজ্ঞা কাকে বলে?

ভবাষ্যতে কোনো কাজের আদেশ, নিষেধ, অনুরোধ বোঝালে তাকে ভবিষ্যত অনুজ্ঞা বলে। যেমন- তুমি লিখবে। কখনো মিথ্যা কথা বলো না। আল্লাহ তোমার সহায় হোন।

ভবিষ্যৎ কাল কাকে বলে?

যে ক্রিয়া ভবিষ্যতে হবে বা ঘটবে তার কালকে ভবিষ্যৎ কাল বলে। যেমন- আমি স্কুলে যাব। তুমি ভাত খাবে।

What is Radioactivity?

What is Radioactivity? Radioactivity is the process of spontaneous disintegration of certain (unstable) atomic nuclei accompanied by the emission. Radiation is emitted by the unstable and excited nuclei can normally cause ionization in a matter through which they pass. This radiation's can cause extensive damage to the molecular structure of a substance either as a result of the direct transfer of energy to its atoms or molecules or as a result of the secondary electrons released by ionization. In biological tissue, the effect of ionizing radiation can be very serious. The ionizing radiation can cause harmful somatic and genetic effects on human body. Sources of Radiation We like in an environment of low level ionizing radiation. Ionizing radiation has been present in the earth since its creation and the human beings are continuously being exposed to such radiation. The natural background radiation comes mainly from three sources viz - ♦ Cosmic radiation - here in the reaction 14N(

Transmission of Heat

Transmission of Heat Heats are transferred from one region to another in three ways. They are conduction, convection, and radiation. ♦ Conduction When one end of a metal rod is heated, the unheated end soon becomes warm. This is because heat travels through the metal by the process of conduction. All electrons are constantly vibrating and in metals the electrons are mobile. When a metal is heated the kinetic energy of its electrons is increased and they begin to move more rapidly and to move towards the cooler parts of the metal. Hence their energy is transferred to the cooler molecule. ♦ Convection In the process of convection heat is carried by and transferred by the movement of a liquid of gas. When liquid is heated at the bottom of a container a current of hot liquid moves upwards to be replaced by a current of cold liquid moving down. ♦ Radiation Radiation is the way in which heat travels from the sun across space to the earth’s atmosphere. This “radiant energy” consists of invisi

অনুরূপ কোণ কাকে বলে?

দু’টি সমান্তরাল সরল রেখাকে অপর একটি সরল রেখা ছেদ করলে ছেদকের একই পাশে যে কোণ উৎপন্ন হয় তকে অনুরূপ কোণ বলে। অনুরূপ কোণগুলো পরস্পর সমান হয়।

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