For concrete of grade M50, the value of flexural tensile strength will be nearly 

Concept:

As per IS 456 : 2000, clause 6.2.2:

Tensile Strength of Concrete in Flexure: The flexural and splitting tensile strengths shall be obtained as described in IS 516 and IS 5816 respectively. When the designer wishes to use an estimate of the tensile strength from the compressive strength, the following formula may be used:

Flexural strength (f_cr) = \(0.7\sqrt{f_{ck}}\) N/mm²

where f_ck is the characteristic cube compressive strength of concrete in N/mm².

Calculation:

Given

Grade of concrete is M50

Flexural tensile strength (f_cr) = 0.7\(\sqrt{f_{ck}}=0.7\sqrt{50}=4.949\) N/mm²

Flexural tensile strength (fcr) = 4.949 ≈ 5 N/mm²

Hence option (1) is the correct answer.