Physical Measurements in Sound, Light, Magnetism and Electricity

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Standard Press, 1906 - Physical measurements - 200 pages
 

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Page 145 - As a unit of current, the international ampere, which is one-tenth of the unit of current of the cgs system of electromagnetic units, and which is represented sufficiently well for practical use by the unvarying current which, when passed through a solution of nitrate of silver in water, and in accordance with accompanying specifications, deposits silver at the rate of 0.001118 of a gramme per second.
Page 16 - B with the sound velocity where y is the ratio of the specific heat at constant pressure to the specific heat at constant volume, and p is the gas pressure.
Page 112 - And they placed them on the heavenly tablets, each had thirteen weeks; from one to another (passed) their memorial, from the first to the second, and from the second to the third, and from the third to the fourth.
Page 32 - The index of refraction n^ of a medium is the ratio of the speed of light in a vacuum to the speed of light in the medium, n^ = C/Cm.
Page 74 - Adjust its distance from the object screen (a narrow slit with a cross hair) until an image of the slit is formed on the screen beside the slit. The light between the lens and mirror is then parallel and the distance from the lens to the screen is the focal length of the lens. 3. Focus a telescope accurately for parallel light. Place the lens in front of the objective of the telescope and view through the telescope some fixed mark—a narrow slit or a fine point. Adjust the distance between the lens...
Page 86 - When an object is viewed through a lens or a microscope the magnifying power of the optical instrument is defined as the ratio of the angle which the image subtends at the eye to the angle which the object...
Page 120 - ... than 1. In air, etc., B = H. Where the magnetic lines emerge into the air at a polar surface they are of course continuous with the internal lines : the value of B just inside the polar surface is the same as that of B in the air just outside it. The permeability of such non-magnetic materials as * The actual number of magnetic lines that run through unit area of cross-section in the iron or other material — denoted by the symbol B — Is called by several names — " the permeation," " the...
Page 164 - Power in watts = f. : — °J' ,J time in seconds Thus 1 watt equals 1 Joule/sec. 1 kilo watt-hour (kWh) = 1000 watt-hours = 36000000 joules. Coulomb. The coulomb (C) is the derived unit of charge. It is defined as the quantity of electricity passing a given point in a circuit when a current of 1 A is maintained for 1 second. Q = Lt where Q = charge in coulombs, / = current in amperes, and t = time in seconds.
Page 179 - Rotate the coil continuously and uniformly, recording the number of turns per minute and the deflection of the galvanometer. II. Set the coil so that its axis of rotation is approximately in the direction of the earth's magnetic field (at an angle of about 62° with the horizontal). Rotate it continuously as was done in I (c\ recording again the number of turns per minute and the deflection of the galvanometer, if any.
Page 179 - Set the coil with the axis of rotation vertical, and rotate the coil at the same rate as in one of the cases in (c). To what component of the earth's magnetic field is the induced electromotive force proportional in this case? To what component was it proportional in (c) ? From the relative currents obtained in the two cases calculate the angle of dip. (e) By varying the angle of inclination of the coil, find a position for which there will be no electromotive force induced when the coil is rotated....

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