‘P’ is the pre-stressed force applied to tendon of a rectangular pre-stressed beam whose area of cross section is ‘A’ and sectional modulus is ‘Z’. The minimum stress ‘f’ on the beam subjected to a maximum bending moment ‘M’ is

A. A circular curve B. A straight line C. A parabolic curve D. An elliptical curve

A. Equal or less than 5 kg/cm², no shear reinforcement is provided B. Greater than 4 kg/cm², but less than 20 kg/cm², shear reinforcement is provided C. Greater than 20 kg/cm², the size of the section is changed D. All the above

A. Low strength concrete only B. High strength concrete only C. Low strength concrete but high tensile steel D. High strength concrete and high tensile steel

A. $${\frac{1}{4}^{{\text{th}}}}$$ of the span B. $${\frac{1}{5}^{{\text{th}}}}$$ of the span C. $${\frac{1}{6}^{{\text{th}}}}$$ of the span D. $${\frac{1}{7}^{{\text{th}}}}$$ of the span