Consider the following statements:

I. Modulus of elasticity concrete increases with increase in compressive strength of concrete.

II. Brittleness of concrete increases with decrease in compressive strength of concrete.

III. Shear strength of concrete increases with increase in compressive strength of concrete.

The TRUE statements are

A singly reinforced rectangular concrete beam has a width of $$150$$ $$mm$$ and an effective depth of $$330$$ $$mm.$$ The characteristic compressive strength of concrete is $$20$$ $$MPa$$ and the characteristic tensile strength of steel is $$\,\,\,\,\,\,\,415\,\,MPa.$$

Adopt the stress block for concrete as given in $$IS$$ $$456$$-$$2000$$ and take limiting value of depth of neutral axis as $$0.48$$ times the effective depth of the beam.

The limiting value of the moment of resistance of the beam in $$kN$$-$$m$$ is

A singly reinforced rectangular concrete beam has a width of $$150$$ $$mm$$ and an effective depth of $$330$$ $$mm.$$ The characteristic compressive strength of concrete is $$20$$ $$MPa$$ and the characteristic tensile strength of steel is $$\,\,\,\,\,\,\,415\,\,MPa.$$

Adopt the stress block for concrete as given in $$IS$$ $$456$$-$$2000$$ and take limiting value of depth of neutral axis as $$0.48$$ times the effective depth of the beam.

The limiting area of tension steel in $$m{m^2}$$ is

A concrete beam of rectangular cross-section of size $$120$$ $$mm$$ (width) and $$200$$ $$mm$$ (depth) is prestressed by a straight tendon to an effective force of $$150$$ $$kN$$ at an eccentricity of $$20$$ $$mm$$ (below the centroidal axis in the depth direction). The stresses at the top and bottom fibres of the section are