Question 91. A border strip of 8 × 250 m is being irrigated by a border stream of 50 lps. The infiltration capacity of the soil is 25 mm h-1 (assumed to be constant throughout the period of irrigation). The average depth of the advancing sheet of water over the land is 70 mm. The time required to irrigate the border strip, in minutes, will be

Question 92. Decimal reduction times for Bacillus subtilis are 37 s and 12 s at temperatures of 1200C and 1250C, respectively. The temperature rise, in 0C, necessary to reduce the first value of decimal reduction time at 1200C by a factor of 10 is

Question 93. A tractor power take-off (PTO) driven stationary peg tooth type wheat thresher operating at a cylinder speed of 540 rpm requires a torque of 250 Nm at PTO. The minimum net engine power required, in kW is

Question 94. A 200 mm well fully penetrates a confined aquifer. After a long period of pumping at a rate of 1400 litres per minute, the drawdowns in the observation wells located at 25 m and 40 m from the pumping well are found to be 2.6 m and 1.9 m, respectively. The transmissivity of the aquifer in m2 day-1 is

Question 95. Air at 700C and 0.015 humidity ratio is cooled adiabatically by spraying water. The final temperature of the air is 550C. Specific heat capacities of dry air and water vapour are 1.005 and 1.88 kJ kg-1 K-1, respectively and latent heat of vapourization of water at 00C is 2501.7 kJ kg-1. The absolute humidity of the outlet air, in kg water vapour per kg dry air is

Question 96. A single effect vacuum evaporator has 100 tubes of 25 mm diameter. One thousand kg feed of milk per hour with 15% TS is concentrated to 20% TS in the evaporator. Film heat transfer coefficients on either sides of the tube are 5000 and 800 W m2 K-1. Thermal conductivity of 1.5 mm thick SS tubes is 15 W m-1 K-1. Latent heat of vapourization under vacuum is 2309 kJ kg-1. For 100C temperature difference across the tube wall, the height of each tube, in m is

Question 97. It is proposed to construct bench terraces on a 10% hill slope. If the batter slope is ½ H : 1 V, the percentage area that will be lost for cultivation due to bench terracing is

Question 98. One thousand units of mixed fruit bar, each weighing 100 g with a surface area of 0.01 m2, are frozen from 700C molten mass condition to -200C frozen storage condition within 3 hours. The specific heat capacity values of the bar are 3.6 kJ kg-1 K-1 and 1.97 kJ kg-1 K-1 before and after freezing point (0 °C) respectively. If the latent heat of crystallization is 250 kJ kg-1, the cooling capacity of the refrigeration unit required in tons of refrigeration is

Question 99. In a screen separator, the mass flow rates of feed, overflow and underflow are 150, 140 and 10 kg h-1, respectively. Mass fraction of material in the feed and overflow are 0.9 and 0.96, respectively. The effectiveness of separation in percentage is

Question 100. A 9 * 20 cm fluted roller type seed drill is operated at a forward speed of 3 km h-1 in a field of size 120 m * 90 m. The effective ground wheel diameter of the seed drill is 0.5 m and the ratio of ground wheel rpm to the fluted roller rpm is 2. For one complete rotation of each fluted roller, 6.8 g seed is transferred from the seed box to the seed tube. The average time taken for each turn while operating length-wise is 50 s and the total time wasted in refilling the seed box for sowing the entire field is 40 min. The actual field capacity of the machine in ha h-1 is