Chemical Engineering Basics

471. Percentage of argon (by volume) in dry atmospheric air is about

1. 0.09
2. 0.3
3. 0.57
4. 0.94

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472. Percentage of differential pressure lost in a Venturimeter with a tapering of 15° may be about

1. 1
2. 10
3. 25
4. 50

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473. Photographic plates are coated with

1. Silver nitrate
2. Silver halide
3. Calcium silicate
4. Metallic silver

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474. Pick out the correct combination about the role of various additives used in polymers.

1. Plasticiser: increases the polymer strength
2. Heat stabiliser: increases the maximum service temperature
3. Fillers: Does not affect the property of polymer but increases its weight
4. Lubricants: increases the flexibility of polymers

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475. Pick out the correct statement

1. Jet engine can work, where there is no atmosphere
2. Rocket engines cannot work, where there is no atmosphere
3. Rocket engines carry oxygen required for the combustion in the form of oxidiser
4. Jet engines also carry oxidiser

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476. Pick out the correct statement about the condensation.

1. Filmwise condensation gives a lower heat transfer rate than the dropwise condensation
2. Suitable coating or vapour additive is used to promote film wise condensation
3. If a condensing liquid does not wet the surface dropwise, even then condensation will take place on it
4. Reynolds number of condensing liquid is based on its mass flow rate

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477. Pick out the correct statement.

1. Materials exhibiting high elasticity obey Hooke's law
2. The elastic behaviour of rubber under compression is the same as its behaviour under tension
3. The damping capacity of a material is due to its plastic deformation
4. The stress required to cause plastic flow in polycrystalline material is higher as compared to monocrystalline materials due to the presence of grains of different orientations

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478. Pick out the wrong conversion of absolute & kinematic viscosities.

1. 1 stoke = 1 cm²/sec
2. 1 N.sec/m² = 10 paise
3. 1 stoke = 1 m²/sec
4. 1 m²/sec = 10⁴ stokes

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479. Pick out the wrong statement

1. Processing of thermosetting plastics is ideally done by injection moulding
2. Processing of thermoplastics is ideally done by compression moulding
3. Mass production of seamless pipes are done by electrical resistance welding (ERW)
4. Stretch forming is a process of cold drawing

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480. Pick out the wrong statement about coating/electroplating of metals.

1. Phosphate coating is used as an excellent base for paints & enamels
2. Phosphate coating is less corrosion resistant than chromate coating
3. The base metal to be electroplated is normally made the cathode of the electrolytic cell and coating metal is made the anode
4. Calorising is the process of coating steel with chromium

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