Static modulus of elasticity of Concrete in compression

1. What is the ratio of 150 mm cube strength and 300x150 mmxmm cylinder strength of concrete?
2. What is the basic stress in this experiment? (Fc= cylindrical compressive strength)
3. Which Indian Standard (IS) code is adopted for the determination of static modulus of elasticity of hardened concrete in compression?
4. What is the recognized age of the test specimen at the time of the test in days as per IS:516?
5. What is the most preferred length to diameter ratio of cylindrical concrete specimen as per IS:516.