The differential equation $${{{d^4}y} \over {d{x^4}}} + P{{{d^2}y} \over {d{x^2}}} + ky = 0\,\,$$ is

The void ratio of a soil sample is 1. The corresponding porosity of the sample is _______.

Grading of aggregate in a concrete mix is necessary to achieve

$$IS$$ $$456$$-$$2000$$ recommends providing certain minimum steel in a $$RCC$$ beam