In my electronics engineering program, we have topics on quantum mech, statistcal mech and so on(only intuitive treatment, not mathematical)....We follow'Introduction to modern physics' by Sir Arthur Beiser. I have a small doubt in the wavefunction of a system.. Let a system consist of two particles A and B and let their wave-fuctions by ψa and ψb respectively..Let ψc represent the wavefuction of the system.. In this book, it is given that ψc is a product of ψa and ψb.. How is this possible? We have learnt about the probability of existence of a particle by integrating the wave-function..Does this concept have anything to do with the wavefunction of the system.. Please explain me in an intuitive way without tough mathematics..