Magnetic field is maintained stable by field frequency locking which is achieved by selecting substance with a powerful NMR signal and placed physically apart from the test sample (external lock) or dissolved within the test sample (internal lock). [2] 3. The Detector System The system consists of an appropriate electronic circuitry, a computer and peripheral devices to detect amplify and display the NMR signals. It is very sensitive and can sense the difference of frequency signs. The standard and test sample’s frequency can be differentiated by the detectors.
Giant magnetoresistance, which is best to be called as GMR, where GMR refers to the resistance of two terminal devices consisting of alternating layers of non-magnetic and ferromagnetic films. The effect is manifested as a significant electrical resistance change depending on the relative magnetization direction of the adjacent ferromagnetic layers. The resistance is high when the ferromagnetic layers are in antiparallel configuration (magnetization direction opposite) and low for parallel configuration (magnetization direction
The stronger the magnet the greater the field. The static magnetic field can have mechanical effects on the pacemaker. It has been known to effect certain parts of the pacemaker allowing it to revert to different intervals of pacing. It also has the ability to reprogram or reset the device all together. The static magnetic field exerts a magnetic force that can dislodge the pacemaker leads.
1. Explain how medical magnetic resonance imaging (MRI) exploits the magnetic properties of the nucleus. MRI’s rotate the nucleus of an atom, producing a magnetic field. During a MRI, a person is placed between the poles of a strong magnet. The magnetic field permeates the tissue and causes the nucleus scale magnets in the tissues to rotate.
Speed of sound in air using Resonance Purpose: In this laboratory investigation, we will determine speed of sound using the formula: speed = frequency times wavelength. Equation 1 After making several measurements of the speed of sound, we will compare our average experiment result from this lab to the speed of sound predicted by the equation vsound=330 m/s+.6m/s (T).Equation 2 Theory: Congitudinal waves are waves which the motion of the individual particles of the medium is in a direction that is parallel to the direction of energy transport. The result of a longitudinal wave is the creation of compressions and rarefactions within the air. Picture: The speed of sound in air is impacted by the temperature because sound travels by vibrating molecules and passing the energy on to a nearby molecule. Sound travels faster through warm air than cold air because the molecules in warm air vibrate faster.
Liam Stephenson controlled assessment Introduction In my course work I will be looking at how the thickness of a converging lens affects the focal length. The factors involved in this experiment are: light, lens curvature, refraction and thickness of the lens, these will determine the focal length; the focal length is the length between the focus and the lens. Light-visible light is an electromagnetic wave in the electromagnetic spectrum The speed of light depending on the medium it is in, for example the speed of light is 300,000 km/s however when light travels through other medium such as water or glass the speed of light is slowed this is because water and glass is denser than a vacuum of air. Due to it being more dense and a change in speed, the direction of the wave will change this is
Explain why these are referred to as Excitatory Postsynaptic Membrane Potentials (EPSPs). These are labeled as EPSPs due to the location in which these electrical impulses are generated - @ the post synapse membrane and because they depolarize the oldmembrane. 14. Opening Cl- or K+ channels on the postsynaptic membrane will generate hyperpolarizations. Explain why these are referred to as Inhibitory Postsynaptic Membrane Potentials (IPSPs).
Refraction occurs when waves change speed when changing media. Diffraction occurs when waves bend around a barrier. 81. ANS: At the node, destructive interference takes place. At the crest (antinode), constructive interference takes place.
75uS is the time constant used for a high-pass filter to enhance the high frequency audio before transmission to help reduce noise upon reception. The PLL is the portion of the IC which locks your chosen transmission frequency to the crystal reference X1. The PLL portion also contains an oscillator circuit which works in conjunction with the external parts of D5 and the STUB (that weird trace on the back of the board). D5 is called a varactor diode, and is a special variety of diode that is connected backwards. As a reverse DC voltage is applied across the diode, its capacitance varies.
Use the postulates of the kinetic theory to explain the following: i)Matter can exist in three states ii)The pressure exerted by a confined gas decreases as its temperature is lowered iii)A gas of low molecular mass will diffuse through air faster than a gas of high molecular masseven though both are at same temperature. The Kinetic Theory can be used to describe the three physical states of matter namely, solid, liquid and gas. In this theory, some basic assumptions has to be made: a) all matter is made up of extremely small particles b) these particles are in constant random motion c) all collisions between these particles are elastic, and d) mutual attractive forces exist between particles The explanation below gives more information about the three states of matter: i) solids > particles are held together in a regular pattern by strong attractive forces. > particles vibrate about in fixed positions. ii) liquids > vibrating particles have sufficient energy to move from their fixed positions to other parts within a liquid.