UPHESC Assistant Professor 2025
The property measured in TGA (Thermogravimetric Analysis) is:
- (A) Change in temperature
- (B) Change in heat evolved or absorbed
- (C) Rate of change in weight
- (D) Change in weight
Correct Answer: (D) Change in weight
Explanation:
In Thermogravimetric Analysis (TGA), the mass (weight) of a sample is monitored as a function of temperature or time as the sample is heated in a controlled atmosphere.
Key points to distinguish thermal methods:
- TGA: Measures Change in Weight. It is used to study decomposition, oxidation, or loss of volatiles.
- DTA (Differential Thermal Analysis): Measures the Temperature Difference between a sample and a reference.
- DSC (Differential Scanning Calorimetry): Measures Heat Flow (heat evolved or absorbed).
- DTG (Derivative Thermogravimetry): Measures the Rate of change in weight (the first derivative of the TGA curve). This corresponds to option (C).