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Showing posts from 2013

What is the difference between magneto and a.c generator?what is meant by frequency of alterneting current?

A magneto is an electrical generator that uses permanent magnets to produce periodic pulses of alternating current.

Hand-cranked magneto generators were used to provide ringing current in early telephone systems.
Magnetos adapted to produce pulses of high voltage are used in the ignition systems of some gasoline-powered internal combustion engines to provide power to the spark plugs. Use of magnetos for ignition is limited mainly to engines where there is no low-voltage electrical system available, such as lawnmowers and chainsaws. Magnetos have traditionally been used in aviation piston engines even though a low-voltage electrical system is usually available, to keep the ignition system independent of the battery and charging system and to keep the engine running in the event of alternator or battery failure. For redundancy purposes, virtually all piston engine aircraft are fitted with two magneto systems, each supplying power to one of two spark plugs in each cylinder.

Magnetos were ra…

Electric Power Transmission (College Level )

The electrical power generated in a power station situated in a remote place is transmitted to different regions for domestic and industrial uses. Here we discuss the electric power grid, power generation, transmission, and distribution.Power GridWhat is a power grid?
The power grid forms a bridge between electrical suppliers and consumers through interconnected networks.
The electrical power grid consists of three main parts:
Generating plant for electric power.Transmission of the electric power.Distribution of the electric power. Electrical Power Generation in Power StationsNormally, electric power generating plants are located near the source of power generation like dams, coal mines, etc. They may be in remote locations, and the generated power has to be supplied to the consumer in the city.
Sources for Power Generation:
The following types of resources are available for generating electrical energy for distribution:
Steam Power Plants Looking For Used Processing Plants? Find Them…

Wave Nature of Particle - the de Broglie Hypothesis( College Level)

In experiments like photoelectric effect and Compton effect, radiation behaves like particles. de Broglie, a french physicist asked whether in some situations, the reverse could be true, i.e., would objects which are generally regarded as particles (e.g. electrons) behave like waves ? In 1924 de Broglie postulated that we can associate a wave with every material object. In analogy with photons, he proposed that the wavelength associated with such a matter wave is related to the particle momentum through the relationship

where is the Planck's constant

Wavelike behaviour of a macroscopic object is difficult to detect as the wavelength is very small.
However, wave nature of particles may be detected in diffraction experiments where the dimensions of the obstacles are comparable with the wavelength of matter wave incident on the obstacle.

Example :Electron Diffraction from a Crystal

Consider a beam of electron with a speed m/s corresponding to a wavelength nm. Such a wave may be di…

Uses of DC Load line

The below figure shows the output characteristic curves for the transistor in CE mode. The DC load line is drawn on the output characteristic curves. 

Load line To draw load line, we have to find saturation current and the cutoff voltage. After plotting these values on the vertical and the horizontal axes, a line is drawn joining these two points, which represents DC load line. It represents all possible combinations of the collector current Ic and the collector voltage Vc (or Vce) for the given load resistorRc. 

Saturation point The point at which the load line intersects the characteristic curve near the collector current axis is referred to as the saturation point. At this point of time, the current through the transistor is maximum and the voltage across collector is minimum for a given value of load. Therefore saturation current for the fixed bias circuit, Ic (sat) =Vcc/Rc 

Cutoff point The point where the load line intersects the cutoff region of the collector curves is referred a…

Basic Unit Conversions

Ans:In the field of science, the metric system is used in performing measurements. The metric system is actually easier to use than the English system, as you will see shortly. The metric system uses prefixes to indicate the magnitude of a measured quantity. The prefix itself gives the conversion factor. You should memorize some of the common prefixes, as you will be using them on a regular basis. Common prefixes are shown below:
Metric - Metric ConversionsSuppose you wanted to convert the mass of a 250 mg aspirin tablet to grams. Start with what you know and let the conversion factor units decide how to set up the problem. If a unit to be converted is in the numerator, that unit must be in the denominator of the conversion factor in order for it to cancel.

Notice how the units cancel to give grams. I've shown the conversion factor numerator as 1 x 10…

Projectile Motion (College Level)

Projectile is a body thrown with an initial velocity in the vertical plane and then it moves in two dimensions under the action of gravity alone without being propelled by any engine or fuel.Its motion is called projectile motion.The path of a projectile is called its trajectory. Examples: A packet released from an airplane in flight. A golf ball in flight. A bullet fired from a rifle. A jet of water from a hole near the bottom of a water tank. Projectile motion is a case of two-dimensional motion .Any case of two dimensional motion can be resolved into two cases of one dimensional motion -one along the x-axis and the other along the y-axis.The two cases can be studied separately as two cases of one dimensional motion.The results from two cases can be combined using vector algebra to see the net result What is import…

Introduction to Space Physics - M. Kivelson, C. Russell

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Description:Designed as a text for upper-level undergraduate and first-year graduate students, this volume attempts to establish the curriculum for the modern student entering the fledgling field of space physics. The book provides a broad, yet selective, treatment of the subject, covering virtually all aspects of space plasmas in the solar system. There are sections on the sun and solar wind, the magnetized and unmagnetized planets, and the fundamental process of space plasmas including shocks, plasma waves, ULF waves, wave-particle interactions, and auroral processes. In addition to emphasizing analysis, the authors also place importance on underlying phenomenology with extensive attention to observations.

Physics for Scientists and Engineers 6th ed. (College Text) - Serway and Jewett

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This best-selling, calculus-based text is recognized for its carefully crafted, logical presentation of the basic concepts and principles of physics. PHYSICS FOR SCIENTISTS AND ENGINEERS, Sixth Edition, maintains the Serway traditions of concise writing for the students, carefully thought-out problem sets and worked examples, and evolving educational pedagogy. This edition introduces a new co-author, Dr. John Jewett, at Cal Poly Pomona, known best for his teaching awards and his role in the recently published PRINCIPLES OF PHYSICS, Third Edition, also written with Ray Serway. Providing students with the tools they need to succeed in introductory physics, the Sixth Edition of this authoritative text features unparalleled media integration and a newly enhanced supplemental package for instructors and students!

What are the uses of capacitor?

Ans:One of the most ubiquitous passive components used is the capacitor, found in nearly every electronic device ever made. Capacitors have a number of essential applications in circuit design, providing flexible filter options, noise reduction, power storage and sensing capabilities for designers.
Filter Applications
Combined with resistors, capacitors are often used as the main element of frequency selective filters. The available filter designsand topologies are numerous and can be tailored for frequency and performance by selecting the proper component values and quality. Some of the types of filter designs include: High Pass Filter (HPF) Low Pass Filter (LPF) Band Pass Filter (BPF) Band Stop Filter (BSF) Notch Filter All Pass Filter Equalization Filter
Decoupling/By-Pass Capacitors - Capacitors play a critical role in the stable operation of digital electronics by protecting sensitive microchips from noise on the power signal which can cause anomalous behaviors. Capacitors used in this app…

Explain whether atomic number can increase during nuclear decay .Support your answer with example.

Ans.When a beta particle is emitted out of any nucleus,then it's mass number does not undergo any change but it's charge number increase by one.Negative Beta is an electron and its emission from the nucleus becomes an in comprehensive enigma, as there is no electron in the nucleus >how ever , the emission of electrom from the nucleus can be thought of as neutron emitting an electron and becoming a proton, although the modern explanation is not that simple.
This means that beta particle is formed at the time of emission.That is why at the time of emission of a beta particle the charge number of nucleus increases by one.

For Example:

Schaum's Outline of Vector Analysis Murray R. Spiegel


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what is a directional derivative/gradient?

Directional Derivative The directional derivative  is the rate at which the function  changes at a point in the direction . It is a vector form of the usual derivative, and can be defined as (1) (2) where  is called "nabla" or "del" and  denotes a unit vector. The directional derivative is also often written in the notation (3) (4) where  denotes a unit vector in any given direction and  denotes a partial derivative. Let  be a unit vector in Cartesian coordinates, so (5)