Param Himalaya - परम हिमालय

What is a simple microscope ? With the help of a diagram, explain the working of a simple microscope. Also write the uses of simple microscope. A simple microscope is a converging lens of small focal length to see very small objects as magnified one. It consists of a convex lens of small focal length. A magnifying glass is an example of a simple microscope. Principle : A simple microscope is based upon the fact that an object placed between the optical centre and the focus of a convex lens, forms a virtual, erect and magnified image on the same side of the lens. The image is formed at the least distance of distinct vision (i.e. 25 cm) from the eye. Working : Consider a convex lens of focal length $f$. Let AB be an object which lies between the optical centre (C) and the focus (F) of the lens. The rays of light from the object do not meet after refraction through the lens. They appear to come from a point B' so that A'B' is the virtual image of the object AB. This image is e...

Topic : Define prism , the angle of prism , Refraction Through Prism ,Prism Formula ( Condition for Minimum Deviation Define Prism and the angle of prism :  A simple prism is a homogeneous transparent refracting medium bounded by at least two non parallel plane surfaces inclined at some angle. The surface on which light is incident and another surface from which light comes out should be non parallel.The two non parallel plane surfaces participating in refraction of light are called refracting surfaces and the line of intersection of the two refracting surfaces is called refracting edge. The angle between two refracting surfaces is called the angle of prism or refracting angle and is denoted by A. Refraction Through Prism: Discuss refraction of light due to a prism and hence show that $\delta + A = i + e$, Determination of angle of deviation ($\delta$). Let ABC be the principal section of a prism of refracting angle A. Let a ray of light DE be incident on the refracting surface AB ...

What is a compound microscope ? With the help of a labelled ray diagram, show the image formation by a compound microscope. Derive an expression for its magnifying power. Compound Microscope : A compound microscope consists of two suitable lenses to give large magnification by compounding the magnification given by the two lenses. Construction : compound microscope consists of two convex lenses called objective and the eye piece. An objective lens is of small aperture and small focal length and faces the object to be seen. It forms a real, inverted and magnified image of an object. An eyepiece is a convex lens of large aperture and large focal length as compared to objective. It gives enlarged and virtual image by compounding the effect of the objective. Principle : When an object is placed in front of a convex lens O at a distance between $F_o$ and $2F_o$, the real, inverted and magnified image is formed on the other side of this lens. If this image lies within the focal length of a...

Define Astronomical Telescope , it's construction and principal. Expression for magnifying power ( Angular Magnification) For Distinct Vision Adjustment and For normal Adjustment  Construction: It consists of two achromatic convex lenses mounted co-axially in two metallic tubes. The lens facing the object (which is at infinity) is called objective lens. It has large aperture and large focal length. The other lens through which the image is observed is called eyepiece. It is of small aperture and has small focal length. The tube having eyepiece can be moved in and out of the tube holding objective lens with the help of rack and pinion arrangement. Principle and Theory: Principle of astronomical telescope can be discussed by considering two extreme cases:  (a) When the final image is formed at least distance of distinct vision ( Distinct Vision Adjustment) (b) When final image is formed at infinity (Normal adjustment). Define magnifying power of an astronomical telescope. Deriv...

Derivation - Lens Maker's Formula | Refraction by a lens - Param Himalaya  Derivation : Consider a lens made of a material of absolute refractive index $n_2$. This lens is placed in a medium of absolute refractive index $n_1$ ($n_1 < n_2$). The lens is bounded by two spherical refracting surfaces $XP_1Y$ and $XP_2Y$. $C_1$ and $C_2$ be their centres of curvature and $R_1$ and $R_2$ be their radii of curvature respectively. $C$ is the optical centre of the lens. STEP 1. Refraction at Surface $XP_1Y$ : Let O be a point object lying in the rarer medium on the principal axis of the refracting surface $XP_1Y$. The incident ray OA after refraction at A bends towards the normal $AC_1$ and meets the principal axis at $I_1$ if the second surface $XP_2Y$ were not present. So, $I_1$ is the real image of the object O. Since object lies in the rarer medium, so we have $-\frac{n_1}{u} + \frac{n_2}{v_1} = \frac{n_2 - n_1}{R_1} \qquad ... (i)$ STEP 2. Refraction at Surface $XP_2Y$ :} In fact, t...

कविता Poem : वीर गाथा Veer Gatha  भारत माँ के वीर जवानो , तुमको मै सत्तकार करू, नमन- वंदना स्तुति तुमको, तुमको मै प्रणाम करू ! समय किरदार बलवान होता है, हर पल ने तेरा इम्तिहान लिया, युध्द मे जाकर वीर-गाथा का भी तुमने सम्मान किया ! जज्बा तेरा, हिम्मत तेरी, तेरे वीर साहस को सलाम करू, भारत माँ के वीर जवानो तुमको मै प्रणाम करू ! चैन से सो जाते है हम, तुम जागते रहते हो, तिरंगे की लाज बचाने, हर पल तत्पर रहते हो, आन बान ते शान तुम ही हो, मै ऐसा एलाक करू, भारत माँ के वीर जवानो मै तुमको प्रणाम करू ! नित नये दुश्मन बनते तेरे, नित नये मौत पैगाम लिखे, बब्बर शेर सा जिगरा देख कर , दुश्मन भी तेरे काँप उठे ! सन् 65 हो या हो 71, या मै करगिल की बात करू, देख साहसिक हौसला तेरा, मै " राम" कैसे ना तेरा गुणगान करू, भारत माँ के वीर जवानो तुमको मै प्रणाम करूं !!! जय हिन्दजय भारत 

1. Refraction at a Refracting Surface when Object lies in Rarer Medium :  Question : Prove that $\frac{-n_1}{u} + \frac{n_2}{v} = \frac{n_2 - n_1}{R}$ When image formed is real :  Consider a convex spherical refracting surface of refractive index $n_2$. Let it be placed in a rarer medium of refractive index $n_1$ ($n_2 > n_1$). A point object O lies in rarer medium on the principal axis at a distance $u$ from the pole of the convex refracting surface. A ray of light from O incident on the convex surface at A. Let C be the centre of curvature, then AC is the normal to the convex surface. After refraction at A, the ray enters the denser medium and bends towards the normal. The refracted ray meets the principal axis at I which is the real image of the object O. The distance of the image I from the pole of the convex surface is $v$. STEP 1. Determination of $i$ and $r$. Let $\alpha$, $\beta$ and $\gamma$ be the angles made by the incident ray, refracted ray and the normal respe...