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Describe an experiment to determine to determine the temperature co-efficient of a thermistor using a meter bridge. |
Answer» Solution :Formula `alpha = ( 2.303 ( log R _(1) - log R _(2)))/( T _(1) - T _(2)) and R = ( Sl )/( 1-l ) Omega `  Ba-Battery K- Plug KEY S - Resistance BOX G - Galvanometer Procedure : The connections are made as shown in the circuit diagram. SUITABLE resistance S is unplugged in the STANDARD resistance box. The circuit is checked for opposite deflections by placing the slider at the two ends of the wire A & C. The thermistor is immersed in a beaker containing hot water. The slider is moved on the wire from the end A towards C till the galvanometer shown zero deflection at the point D, the balancing length l is measured. The corresponding temperature of the hot water is noted as `t_(1) ^(0) C (T_(1) = 273 + t _(1))` The resistance of thermistor `R_(1) at T_(1)` is calculated using the formula `R_(1) = Sl//1-l.` The experiment is repeated when the temperature of water decrease by a small value (about `5^(@)C)` and the corresponding resistance `R_(2)` is calculated. The temperature co-efficient of thermistor is CALCULATE using formula `alpha = ( 2.303 ( log R_(1) - log R _(2)))/( T _(1) - T _(2))` 
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