Mechanical Operations

131. For Indian standard (IS) screens, the mesh number is equal to its aperture size expressed to the nearest deca-micron (0.01 mm). Aperture width of IS screen of mesh number 50 will be approximately _________ microns.

1. 5
2. 50
3. 500
4. 5000

View answer

132. For laminar flow of filtrate through the cake deposited on septum, which of the following will be valid?

1. Kozeny-Carman equation
2. Leva's equation
3. Blake-Plummer equation
4. None of these

View answer

133. For raschig rings, the sphericity is

1. 0.5
2. 1
3. < 1
4. √3

View answer

134. For removal of very small amounts of precipitate from large volume of water, the most suitable filter is the _________ filter.

1. Plate & frame
2. Shell & leaf
3. Sand
4. Rotary vacuum

View answer

135. For separation of sugar solution from settled out mud, we use a _________ filter.

1. Sparkler
2. Plate and frame
3. Centrifugal
4. Rotary drum vacuum

View answer

136. For sizing of fine materials, the most suitable equipment is a

1. Trommel
2. Grizzly
3. Shaking screen
4. Vibrating screen

View answer

137. For spheres, the specific surface shape factor is given by

1. AD/V
2. D/V
3. A/V
4. √(AD/V)

View answer

138. For spheres, the surface shape factor is given by (where, A = area, V = volume, and D = diameter)

1. π = (A/D²)
2. π/6 = (V/D³)
3. AD/V
4. None of these

View answer

139. For spheres, volume shape factor is given by

1. π = (A/D²)
2. 2π = (2A/D²)
3. π/6 = (V/D³)
4. AD/V

View answer

140. For the preliminary breaking of hard rock, we use a

1. Gyratory crusher
2. Ball mill
3. Tube mill
4. Squirrel-cage disintegrator

View answer