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A thimble or calorimeter, constant temperature enclosure, a thermometer, st, ater bath etc. eames oa, law of cooling : ‘ ., , 4 of fall of temperature a) by a body is directly proportional to the difference of Pa, , perature (6 -8,) of the body over the surroundings, provided the difference is small. welog, , , , , , , , , , , , , , , , , , , , , <—————-— Thermometer, , IEZTINNZZZ77Z2, , idle, !, , Water, , Calorimeter, , paeeeet, , Doubled walled, <—— container, , , , , , , , Theory:, "The rate at which a hot body loses heat is directly proportional to the difference between the, , temperature of the hot body and that of its surroundings and depends on the nature of material and the, surface area of the body. This is newton’s low of Colling ‘ 2 1 coe 5, , Rate of loss of heat “9 =x 6 -6,), , ms, , Scanned with CamScanner

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+ * ometer., 2. Note down the temperature of the surrounding (room temperature) by using SN, , : a Sh et city. Insert, 3. Fill the thimble or calorimeter with hot water about 75 to 80°C upto e OSS Coa, , thermometer such that its bulb is well inside the hot water., BA ce, Note the initial temperature which is about 750 to 80°C above the room temperatur, , Start the stop watch., , , , Note the temperature after every minutes., , Take required number of readings till temperature of water falls about 40°C., , ne, , Plot the graph of temperature (8°,C) against time (t) in minutes. Draw smooth curve through the, points., 9. Plot the graph of “ against temperature 0.Hence determine the room temperature (6,), 10. Plot a graph of rate of cooling against excess temperature above the surrounding Hence verily, Newton’s law of cooling. ., , Observations :, 1. Least count of stop watch =, , 2. Least count of thermometer =, , , , 3. Temperature of the surrounding (8,) = 28. °c,, , Observation Table (I) :, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Ob. No. Time in min Temperature of | Ob. No. Time in min Temperature of, water °C water °C, 1 0 ‘o iD 15 Ag, 2D \ 68 ud 16 4Q, 3 2 66 Ag " 4}, a 3 64 e Ig 40, 2 2 ee a ae 39.0, 6 5 60 at 26 38.0, iB 6 5S ze a\ 3g, é 7 fe = a 31-0, 9 g 54 zs 23 ace, 10 Q 52 ee 24 36.0, ii 10 50 ta o% 36, 12 u Hyg Ouaatal 26 35.0, B 1a 4] 28 |. a, 14, 15, , , , , , , , , , , , , , , , Scanned with CamScanner