Q1: An R.C.C. beam not provided with shear reinforcement may develop cracks in its bottom inclined roughly to the horizontal at

ANS:C - 45°

An RCC (Reinforced Concrete Cement) beam not provided with shear reinforcement may develop cracks in its bottom inclined roughly to the horizontal at approximately 45°. Explanation: When a reinforced concrete beam is subjected to shear forces without adequate shear reinforcement, diagonal cracks tend to form in the concrete at an angle of approximately 45 degrees to the horizontal. This angle is known as the "angle of diagonal tension cracks." The formation of these cracks occurs due to the shear stresses exceeding the shear capacity of the concrete. The cracks develop diagonally from the support towards the midspan of the beam. So, the correct answer is: 45°