Which of the following statement (s) is/are true about thermal radiations?1. Thermal radiations are electromagnetic waves.2. All bodies emit thermal radiations at all temperature.3. Thermal radiations are reflected from mirror.4. Thermal radiations of all wavelengths travel in free space with same velocity. Choose the correct answer

In thermodynamics, heat is the thermal energy transferred between systems due to a temperature difference. In colloquial use, heat sometimes refers to thermal energy itself. Thermal energy is the kinetic energy of vibrating and colliding atoms in a substance.