ELECTRICAL MEASURING INSTRUMENTS For the detection or measurement of electric current, potential difference, and resistance certain instruments have been devised viz. The galvanometer for the detection of small currents measurements of small currents of the order of micro amperes or mili amperes the voltmeter or potentiometer for the measurement of potential difference (and voltage) between two points of a circuit are the EMF of a source the ammeter for the measurement of large currents the wheatstone bridge the meter Bridge the post office box and the ohmmeter for the measurement of resistance. THE MOVING COIL GALVANOMETER The moving coil galvanometer is a basic electrical instrument it is used for the detection (and Measurement) of small currents. Its underlying principle is the fact that when a current flows in a rectangular coil placed in a magnetic field it experiences a magnetic torque. If it is free to rotate under a controlling torque, it rotates through an angle proportional t...
MANUFACTURE OF SODIUM BICARBONATE AND SODIUM CARBONATE BY SOLVAY-PROCESS : INTRODUCTION : Solvay process was introduced by Belgian engineer Ernest Solvay (1861) for manufacture of sodium bicarbonate (baking soda) and sodium carbonate (washing soda). This process is also known as "Ammonia soda process" due to use of ammonia. DETAILS OF THE SOLVAY PROCESS : Solvay process involves the following steps: 1. AMMONIATION : Concentrated brine (sodium chloride) solution is prepared by dissolving NaCl in water.Then the brine is purified by lime-soda treatment to precipitate calcium and Magnesium as carbonate which settle down.Then the brine is pumped into a tower in which strream of ammonia gas is passed through it, the brine saturated with ammonia is called "Ammonical brine" in which CO2 is more soluble than ordinary brine. 2. CARBONATION : Carbonation involves combination of CO2 with ammonical brine. For this purpose CO2 is prepared in a skin by heating lime-stone. CaCO3 ...