PLEASE ANSWER THESE 4 QUESTIONS 1.due to passing of excess of CO2 through slaked lime is formed which is used as antacid.

2.the speed of electromagnetic waves is ___(in Km/S)

3. The distance of image formed is always infinity for a concave mirror when an object is

4. power of the lens is -5D, then the focal length of the lens is

First answer marked as brainiest which is the correct equation describing the first law of thermodynamics? a) when the internal energy of a system changes, it equals the amount of heat added plus the work done. b) when work is done by the piston, it is equal to the heat added plus the change in internal energy of the system. c) when heat is added to the system, it is equal to the amount of work done by the piston plus the change in internal energy of the system.