Saved Bookmarks
| 1. |
The resistance of the platinum wire of a platinum resistance thermometer at the ice point is 5 Omega and at steam point is 5.39 Omega. When the thermometer is inserted in a hot bath, the resistance of the platinum wire is 5.795 Omega. Calculate the temperature of the bath. |
|
Answer» SOLUTION :Here, `T_(0) `= ice point = `0^(@) C, R_(0) = 5 Omega` `T_(1) = ` steam point = `100^(@)C, " " R_(1) = 5.23 Omega` `T_(2) = ?, R_(2) = 5.795 Omega ` `R_(1) = R_(0) { 1 + ALPHA (T_(1) - T_(0))} ` `therefore 5.23 = 5{ 1 + alpha (100 - 0 )} ` `therefore 1.046 = 1 + alpha (100)` `therefore 0.046 = alpha (100) ""` .... (1) `R_(2) = R_(0) {1 + alpha (T_(2) - 0) }` `5.795 = 5 { 1 + alpha (T_(2) - 0)} ` ` therefore 1.159 = 1 + alpha (T_(2))` ` therefore 0.159 = alpha (T_(2)) "" ` ... (2) Taking ratio of equations (1) and (2), 0.2893 = `(100)/(T_(2))` `therefore T_(2) = (100)/(0.2893) = 345.7^(@) C ` |
|