A question on Quantum Entanglement

I have read a lot about quantum mechanics but have a query. using an entangled photon for this question. If you can’t measure an entangled photon without affecting it’s entanglement then how do we know it was even entangled to start with and not just always a certain “spin”, either up or down. How can [...]

How to describe momentum physically ?

Kiran asks: “How do you describe momentum physically by not in definitions like product of mass and velocity?” Answer: Momentum is defined as “Mass in Motion” or “The quantity of motion“. Momentum is a measure of the “effect” a moving body can produce. It is a measure of the “effort” required to bring a body to [...]