Q. Critical speed of a ball mill depends on A. the radius of the mill (shell) and the radius of the particles B. the radius of the mill (shell) and the density of the particles C. the radius of the balls and the radius of the particles D. the radius of the balls and the […]
Q. The terminal velocity of a spherical particle in gravitational settling under Stokes’ regime varies A. linearly with the particle diameter B. linearly with the viscosity of the liquid C. directly with the square of particle diameter D. inversely with the density of particle Ans: directly with the square of particle diameter
Q. A watch uses two electronic circuits (ECs). Each EC has a failure probability of 0.1 in one year of operation. Both ECs are required for functioning of the watch. The probability of the watch functioning for one year without failure is (A) 0.99 (B) 0.90 (C) 0.81 (D) 0.80 Ans: 0.81
Q. An aerial photograph of a terrain having an average elevation of 1400 m is taken at a scale of 1:7500. The focal length of the camera is 15 cm. The altitude of the flight above mean sea level (in m, up to one decimal place) is _ Ans: 2520 – 2530 Sol: Average elevation
Q. A 7.5 m wide two-lane road on a plain terrain is to be laid along a horizontal curve of radius 510 m. For a design speed of 100 kmph, super-elevation is provided as per IRC: 73- 1980. Consider acceleration due to gravity as 9.81 m/s2. The level difference between the inner and outer edges
Q. The space mean speed (kmph) and density (vehicles/km) of a traffic stream are linearly related. The free flow speed and jam density are 80 kmph and 100 vehicles/km respectively. The traffic flow (in vehicles/h, up to one decimal place) corresponding to a speed of 40 kmph is Ans: 2000 Sol:
Q. A schematic flow diagram of a completely mixed biological reactor with provision for recycling of solids is shown in the figure. S0, S = readily biodegradable soluble BOD, mg/L Q, Qr, Qw = flow rates, m3/d X0, X, Xe, Xu = microorganism concentrations (mixed-liquor volatile suspended solids or MLVSS), mg/L The mean cell residence
Q. At a small water treatment plant which has 4 filters, the rates of filtration and backwashing are 200 m3/d/m2 and 1000 m3/d/m2, respectively. Backwashing is done for 15 min per day. The maturation, which occurs initially as the filter is put back into service after cleaning, takes 30 min. It is proposed to recover
Q. A coal containing 2% sulfur is burned completely to ash in a brick kiln at a rate of 30 kg/min. The sulfur content in the ash was found to be 6% of the initial amount of sulfur present in the coal fed to the brick kiln. The molecular weights of S, H and O
Q. A flocculation tank contains 1800 m3 of water, which is mixed using paddles at an average velocity gradient G of 100/s. The water temperature and the corresponding dynamic viscosity are 30oC and 0.798×10-3 Ns/m2, respectively. The theoretical power required to achieve the stated value of G (in kW, up to two decimal places) is
