डीएनए (DNA) क्या है? डीएनए (Deoxyribose Nucleic Acid) न्यूक्लियोटाइड्स का एक लंबा बहुलक है जिसकी लंबाई न्यूक्लियोटाइड के संख्या पर निर्भर करती है न्यूक्लियोटाइड की संख्या अधिक होने पर डीएनए भी अधिक लंबे होते हैं। डीएनए (DNA) की संरचना :- न्यूक्लियोटाइड्स :- न्यूक्लियोटाइड के निम्नांकित तीन घटक होते हैं – नाइट्रोजन क्षारक दो प्रकार के…
RNA and its structure :- RNA molecules are single stranded nucleic acids composed of nucleotides. Fig. 1. Structure of ( a ) DNA and ( b ) RNA. RNA molecules are polymer of nucleotides joined to one another by covalent bonds between the phosphate of one nucleotides and the sugar of another. These linkages are…
Twinkling of stars :- it is is a phenomenon of atmospheric refraction. Stars do not really twinkle they just appear to twinkle when seen from the surface of the earth. The star twinkling in the night because of the effect of our atmosphere. when starling enters our atmosphere it is affected by winds in the…
Total internal reflection :- when light travels from and optically denser medium to rarer medium at the interface, it is partly reflected back into the same medium and partly refracted to the second medium, this reflection is called the internal reflection. Conditions for the total internal reflection :- Critical angle ( Ic ) :- The…
DNA फिंगरप्रिंटिंग :- मनुष्य के डीएनए में पाए जाने वाले क्षार अनुक्रम लगभग 99% एक समान होते हैं, किंतु शेष डीएनए में विभिन्नताए होते हैं, इन विभिन्नताओं का तुलनात्मक अध्ययन करने के लिए जिस विधि का उपयोग किया जाता है उसे DNA फिंगरप्रिंटिंग कहते हैं। DNA फिंगरप्रिंटिंग की विधि :- 3. डीएनए को सीमा तक…
Refraction of light :- when a beam of light encounters another transparent medium, a part of light gets reflected back into first medium while the rest enters the other, The direction of propagation of incident ray of light that enters the other medium changes at the interface of the two media. This phenomenon is called…
The mirror equation :- The ray diagram shows the image A’B’ of an object AB formed by a concave mirror . We derive the mirror equation or the relation between the object distance (u), image distance (v) and the focal length (f). From the above figure the two right angle triangle A’B’F and MPF are…
Consider a ray parallel to the principal axis strinking the mirror at M, CM will be perpendicular to the mirror at M. Let θ be the angle of incidence and MQ be the perpendicular from M on the principal axis, then ∠MCP = θ and ∠MFP =2θ Now tanθ =MQ/CQ and tan2θ = MQ/FQ for…
Definitions regarding spherical mirrors. Pole :- The geometric centre of a spherical mirror is called its pole. Denoted by ‘P’ Principal axis :- The line joining the pole and centre of curvature of the spherical mirror is known as the principal axis. Centre of curvature :- the point in the centre of the sphere from…
Reflection of light :- It is the change in direction of a light at an interface between two different media so that the light returns into the medium from which it originated. Laws of reflection of light :- When a ray of light is reflected from a smooth surface then These laws are valid at…
Optics :- Optics is the branch of physics in which study about properties and behavior of light. There are two types of optics in physics – Ray optics :- Ray optics is the branch of optics in which study about propagation of light in terms of rays,whose path are governed by the law of reflection…
Replication of DNA :- Watson and Crick had proposed a scheme for Replication of DNA. The scheme suggested that the two strands would separate and as a template for the synthesis of new complementary strands. After the completion of replication, each DNA molecule would have one parental and one newly synthesised strand. This scheme was…
