Correct Answer - Option 3 : 0.7√fck
Concept:
Modulus of rupture: It is a measure of the tensile strength of concrete beams or slabs.
Flexural strength of concrete/ Bending tensile strength of concrete/Modulus of rupture of concrete (fcr) is given by
\({{\text{f}}_{\text{cr}}}\text{ }\!\!~\!\!\text{ }=\text{ }\!\!~\!\!\text{ }0.7\times \sqrt{{{\text{f}}_{\text{ck}}}}\)
Modulus of Elasticity of Concrete: It can be defined as the ratio of applied stress to corresponding strain within elastic limits.
It may be given as:
i) Short Term Modulus of elasticity = 5000 √fck
ii) Long Term Modulus of elasticity \(=\frac{5000\sqrt{{{f}_{ck}}}}{1+\theta }\)
where θ is the creep coefficient