measurement & Instrumentation.

Instrument design to read the temperature of a fluid medium is kept in an air oven at 150°c, the instrument was suddenly transferred to a bicker of boiling water on a steady flame. after two seconds, the instrument now read 120°c, assuming that the heating system presents an exponential input function 0f time.
determine;
1. The dynamic response of the instrument to the boiling water.
2. Estimate the initial period the instrument requires to respond.
3. Estimate the output temperature at one time constant under the commission of the system.
4. Provide the sketch as a related function of time.