Atoms are combining to form molecules
Answer: .........................................................................................
Explanation:
Answer: option (A)
Explanation: The convection current is generates in the mantle due to the heat radiated from the core of the earth. Due to this convection current, the lithospheric plates moves as the upper part of the mantle known as the asthenosphere, is the region which is viscous in nature and drives the plates to move. This is a repeating cycle that constantly forces the plates to move.
Thus the correct answer is option (A).
Answer: 20.7 kJ
Explanation:
According to first law of thermodynamics:
=Change in internal energy
q = heat absorbed or released
w = work done or by the system
w = work done on the system=
{Work is done on the system is positive as the final volume is lesser than initial volume}
w = 4.51 kcal = 
(1kcal = 4.184kJ)
q = +1.79 kJ {Heat absorbed by the system is positive}
Thus for a system that receives 1.79 kJ of heat from surroundings and has 4.51 kcal of work done on it at the same time is 20.7 kJ
