Archives November 2013

When a ray of light enters two specifically arranged prisms and disperese i.e. splits into characteristic colours without suffering any deviation inside the prisms(the magnitude of deviation for both the prisms is same and in opposite direction, so net deviation is zero); its called dispersion without deviation...  Deviation without Dispersion. This means an achromatic combination of two prisms in which net or resultant dispersion is zero and deviation is produced As angle of deviation depends upon the prism material, we are in a position to put together prisms of different materials in such a way that the net outcome is such that while dispersion remains, deviations get cancelled out.This can be done when deviation (d1) produced by first prism is equal and opposite to the deviation (d2) produced by the second prism.   The following video is about the Deviation without Dispersion which is being explained to you by a lecturer of a leading educational institute more...

Studyadda has emerged as the biggest online learning platform where we provide students with the best of the study packages. These packages are useful for the academic examinations and competitive examinations like IIT-JEE, VITEEE, WBJEE, J and K Engineering, NTSE, CTET, AFMC, AIPMT.   Chlorobutanol, or trichloro-2-methyl-2-propanol, is a chemical preservative, sedative hypnotic and weak local anaesthetic similar in nature to chloral hydrate. It has antibacterial and antifungal properties. Chlorobutanol is typically used at a concentration of 0.5% where it lends long term stability to multi-ingredient formulations. However, it retains antimicrobial activity at 0.05% in water. In pure state it's a white, menthol like odor, volatile solid. In this video Mr. Lalit Sardana (IIT JEE AIR 243) is explaining students about condensation of acetone which is another topic in haloforms. He is one of the most efficient teachers working in the field of education. This video is not only useful from the school examintion point more...

The Carbylamine reaction is a chemical test for detection of primary amines. In this reaction, the analyte is heated with alcoholic potassium hydroxide and chloroform. If a primary amine is present, the isocyanide is formed. For example, the reaction with ethylamine:  RNH2 + CHCl2 + 4KOH ——> RNC + 3KCl + 3H2O The reaction with aniline:    The carbylamine test does not give a positive reaction with secondary and tertiary amines.  In this video Mr. Lalit Sardana(IIT-JEE AIR 243) an IITJEE trainer will be explaining you some topics related to it. He has done a lot of things that are above the call of duty. This video is useful for students appearing in 11th CBSE, 12th CBSE exams and for the students appering in the competitive exams like JEE Mains, JEE Advanced, VITEEE, WBJEE, KCET, J and K Engineering, MPPET, AIPMT. Watch the video related to The Carbylamine reaction on this link http://www.studyadda.com/videos/jee-chemistry-lectures/haloforms/carbylamine-reaction/1422     more...

A resistor–inductor circuit (RL circuit), or RL filter or RL network, is one of the simplest analogue infinite impulse response electronic filters. It consists of a resistor and an inductor, either in series, driven by a voltage source.   RL circuits form a single-pole filter. Depending on whether the reactive element is in series with the load, or parallel with the load will dictate whether the filter is low-pass or high-pass.   Frequently RL circuits are used for DC power supplies to RF amplifiers, where the inductor is used to pass DC bias current and block the RF getting back into the power supply. Mr. Lalit Sardana(IIT JEE AIR 243) is teaching you the topic Series combination of resistor and inductor. He has explained phasor diagram and sine equation that are related to the topic in this video. The students would not find it difficult to understand as the topic more...

"I was obliged to rise up every few minutes to see that I sailed in the right direction." Sergeant Ezra Lee, pilot of Turtle In 1775 Britain's North American colonies rebelled against British rule, precipitating a War of Independence. An enthusiastic American patriot, David Bushnell (1742-1824) of Saybrook, Connecticut, devised a secret weapon to counter the might of Britain's Royal Navy. He designed and built a submersible vessel to attack warships in harbor. Bushnell's Turtle was an oval-shaped vessel of wood and brass, just large enough to hold one person. It had ballast water tanks that were filled to make it dive, then emptied with a hand pump to return to the surface. Two screw propellers, operated by foot pedals and a handle, allowed the operative to maneuver the vessel laterally and vertically underwater. Ingeniously, the inside of the submersible was lined with naturally luminescent wood to provide light for more...

"The inspiration for the optical disk was an illustration in a technical news magazine..." David Paul Gregg The DVD disk has its roots way back in 1958 when engineer David Paul Gregg, while working for the U.S. Westrex corporation, had the inspiration to create a new format for audio and video. He had seen an article that showed the results from an early scanning electron microscope, which had lines drawn by the electron beam that were less than a tenth of a micrometer wide. Gregg imagined a plastic disk with tracks written on it that could be read with an inexpensive optical reader—the equivalent of a stylus reading the tracks on a traditional vinyl LP. Gregg's original concept, which he patented in 1961, was of a transparent disk, through which a concentrated beam of light would be shone and picked up on the other side by a reader. Like an more...

"The sand had etched the glass... and revealed the contrast against parts... covered by steel mesh" H. J. Plaster, A Tribute to Benjamin Chew Tilghman Legend has it that Benjamin Chew Tilghman (1821-1901), when based in the desert with the U.S. Army, noticed the effect that windblown sand had on the windows of the army buildings, and developed his ideas on sandblasting from there. Tilghman proposed that grains of sand, or quartz, fired at high speed toward a hard surface would allow smoothing, shaping, cleaning, and engraving with greater accuracy and power than current methods. Using compressed air, steam, or water to propel the grains, Tilghman was able to etch away at the surface of a substance harder than the grains themselves. Stone engraving was not new but Tilghman's system replaced the expensive and time- consuming process of hand-chiseling, allowing the user to create effects on any hard surface. From more...

A resistor–capacitor circuit (RC circuit), or RC filter or RC network, is an electric circuit composed of resistors and capacitors driven by a voltage or current source. A first order RC circuit is composed of one resistor and one capacitor and is the simplest type of RC circuit. RC circuits can be used to filter a signal by blocking certain frequencies and passing others. The two most common RC filters are the high-pass filters and low-pass filters; band-pass filters and band-stop filters usually require RLC filters, though crude ones can be made with RC filters. The total impedance (resistance) of this circuit is the contribution from both the capacitor and resistor. From the previous section we have seen that the capacitative reactance Xc is shifted by - 90° from the perturbing voltage signal and therefore is expressed in complex form as  Xc = -j Xc The total circuit impedance is more...

Diamond crystal is a three-dimensional network of carbon atoms. All carbon atoms in the network are strongly bonded by carbon-carbon covalent bonds. Therefore diamond crystal has a highly symmetric cubic structure. The carbon atoms in diamond are precisely aligned. Thus diamond is an ideal crystal. Atoms in the crystal lattices in solids vibrate. These vibrations, called the atomic vibrations facilitate thermal conduction (transport of heat) in solids. In an ideal crystal, the lattices are so precisely aligned that they do not interact with each other. Therefore an ideal crystal conducts better than a non-ideal crystal resulting in ideal crystals having good thermal conductivity, which is a measure of heat conduction. Diamond being an ideal crystal is thus a good thermal conductor. Mobile electrons facilitate electrical conduction - flow of current in solids. There are no free mobile electrons in diamond crystal to ficilitate electrial more...

Capacitance is the ability of a body to store an electrical charge. Any object that can be electrically charged exhibits capacitance. A common form of energy storage device is a parallel-plate capacitor. In a parallel plate capacitor, capacitance is directly proportional to the surface area of the conductor plates and inversely proportional to the separation distance between the plates. If the charges on the plates are +q and -q, and V gives the voltage between the plates, then the capacitance C is given by  C = frac{q}{V}. which gives the voltage/current relationship  :I(t) = C frac{mathrm{d}V(t)}{mathrm{d}t}. Visit below links for more detailed knowledge of capacitance: http://www.studyadda.com/videos/jee-physics-lectures/capacitance/capacitance/1768 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/problems-on-equivalent-capacitance-1/1769 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/problems-on-equivalent-capacitance-2/1770 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/problems-on-equivalent-capacitance-3/1771 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/energy-stored-in-capacitor/1772 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/problems-on-equivalent-capacitance-4/1773Video Lecture Taught By-  Mr. Lalit Sardana (IIT-JEE,AIR 243) ,Sardana Tutorials