Power required by a centrifugal pump is proportional to (where, D = diameter, N = r.p.m) (A) N2D3 (B) ND2 (C) N2D (D) N3D5

Power required by a centrifugal pump is proportional to (where, D =
diameter, N = r.p.m)
(A) N2D3
(B) ND2
(C) N2D
(D) N3D5
by

1 Answer

Answer :

(D) N3D5
by

Related questions

Which is the correct relationship for a centrifugal pump? (Where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed of pump, rpm) (A) D = 1840 H0.5 /N (B) D = 1840 N/H0.5 (C) H = 1840 D0.5 /N (D) D = 1840 H/N

Description : Which is the correct relationship for a centrifugal pump? (Where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed of pump, rpm) (A) D = 1840 H0.5 /N (B) D = 1840 N/H0.5 (C) H = 1840 D0.5 /N (D) D = 1840 H/N

Last Answer : (A) D = 1840 H0.5 /N

Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases. (A) NPSH required (B) BHP required by the pump (C) Head of the liquid pumped (D) All (A), (B) and (C)

Description : Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases. (A) ... the pump (C) Head of the liquid pumped (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

The peripheral velocity at inlet of a centrifugal pump having inlet diameter of 25 cms and rotating at 950 rpm is __________ m/sec. (A) 1.8 (B) 12.4 (C) 186.2 (D) 736.4

Description : The peripheral velocity at inlet of a centrifugal pump having inlet diameter of 25 cms and rotating at 950 rpm is __________ m/sec. (A) 1.8 (B) 12.4 (C) 186.2 (D) 736.4

Last Answer : (B) 12.4

The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost is P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet. (A) P, Q and R (B) P and R (C) R and S (D) P, Rand S

Description : The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost is P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet. (A) P, Q and R (B) P and R (C) R and S (D) P, Rand S

Last Answer : (A) P, Q and R

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the power consumed now will be __________ hp. (A) 0.5 (B) 2 (C) 4 (D) 1

Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the power consumed now will be __________ hp. (A) 0.5 (B) 2 (C) 4 (D) 1

Last Answer : (A) 0.5

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, then the new head will be __________ metres. (A) 2 (B) 4 (C) 8 (D) 5.5

Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, then the new head will be __________ metres. (A) 2 (B) 4 (C) 8 (D) 5.5

Last Answer : (A) 2

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute. (A) 500 (B) 200 (C) 1000 (D) 750

Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute. (A) 500 (B) 200 (C) 1000 (D) 750

Last Answer : (A) 500

With a constant diameter impeller of a centrifugal pump (A) Its capacity varies directly as the square of speed (B) Head varies as the square of speed (C) Horsepower input varies as the square of speed (D) Head varies as the speed

Description : With a constant diameter impeller of a centrifugal pump (A) Its capacity varies directly as the square of speed (B) Head varies as the square of speed (C) Horsepower input varies as the square of speed (D) Head varies as the speed

Last Answer : (B) Head varies as the square of speed

Head developed by a centrifugal pump depends on its (A) Speed (B) Impeller diameter (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : Head developed by a centrifugal pump depends on its (A) Speed (B) Impeller diameter (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : C) Both (A) and (B)

At a constant speed of the centrifugal pump, it’s __________ the impeller diameter. (A) Capacity varies directly with (B) Head varies as the square of (C) Horsepower varies as the cube of (D) All (A), (B) and (C)

Description : At a constant speed of the centrifugal pump, it’s __________ the impeller diameter. (A) Capacity varies directly with (B) Head varies as the square of (C) Horsepower varies as the cube of (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

In case of a centrifugal pump, the theoretical head developed is dependent on the __________ the impeller. (A) Speed of (B) Diameter of (C) Fluid velocity leaving (D) All (A), (B) and (C)

Description : In case of a centrifugal pump, the theoretical head developed is dependent on the __________ the impeller. (A) Speed of (B) Diameter of (C) Fluid velocity leaving (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

The capacity of a centrifugal pump Can be increased by increasing the (A) Impeller diameter or speed (B) Number of pumps and joining them in series (C) Number of pumps and joining them in parallel (D) All (A), (B) and (C)

Description : The capacity of a centrifugal pump Can be increased by increasing the (A) Impeller diameter or speed (B) Number of pumps and joining them in series (C) Number of pumps and joining them in parallel (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

If the head is doubled in & centrifugal pump, the power required will increase in the ratio of (A) 23 (B) 23/2 (C) 25/2 (D) 21/3

Description : If the head is doubled in & centrifugal pump, the power required will increase in the ratio of (A) 23 (B) 23/2 (C) 25/2 (D) 21/3

Last Answer : B) 23/2

To pump water from a water reservoir 3 m deep and maximum water level at 135 m, a pump is installed to lift water up to R.L. 175 m at a constant rate of 36,00,000 litres per hour. If the length of the pipe is 1506 m and f = 0.01, ignoring other minor losses and assuming the economical diameter from Lea's formula D = 1.2 Q, the water horse power of the pump is (A) 400 (B) 450 (C) 500(D) 600

Description : To pump water from a water reservoir 3 m deep and maximum water level at 135 m, a pump is  installed to lift water up to R.L. 175 m at a constant rate of 36,00,000 litres per hour. If the length  of the ... the water horse power of the pump is  (A) 400  (B) 450  (C) 500 (D) 600

Last Answer : (D) 600

If radius of a batch basket centrifuge is halved & the r.p.m. is doubled, then the (A) Linear speed of the basket is doubled (B) Linear speed of the basket is halved (C) Centrifugal force is doubled (D) Capacity of centrifuge is increased

Description : If radius of a batch basket centrifuge is halved & the r.p.m. is doubled, then the (A) Linear speed of the basket is doubled (B) Linear speed of the basket is halved (C) Centrifugal force is doubled (D) Capacity of centrifuge is increased

Last Answer : (C) Centrifugal force is doubled

In centrifugal pump installation, (A) Pump is properly primed before starting (B) The diameter of the pipe at inlet as well as at outlet, is kept smaller than the delivery pipe (C) The motor may burn out if it is started with empty delivery pipe and with open gate valve (D) All the above

Description : In centrifugal pump installation,  (A) Pump is properly primed before starting  (B) The diameter of the pipe at inlet as well as at outlet, is kept smaller than the delivery pipe  (C) The ... out if it is started with empty delivery pipe and with open gate valve  (D) All the above 

Last Answer : (D) All the above 

At low Reynold's number, the power (P) required for agitating a fluid in a stirred tank becomes independent of inertial forces. In this limit, indicate which of the following relations is satisfied: Po = ρ/ρN3 D5 : Power number Re = ρ N D2 /μ: Reynold's number N is the impeller rotational speed, and D is the impeller diameter. (A) Po ∝ Re -1.0 (B) Po ∝ Re 0.0 (C) Po ∝ Re 0.5 (D) Po ∝ Re 1.0

Description : At low Reynold's number, the power (P) required for agitating a fluid in a stirred tank becomes independent of inertial forces. In this limit, indicate which of the following relations is satisfied: Po = ρ/ρN3 D5 : Power number Re = ρ N D2 ... Re -1.0 (B) Po ∝ Re 0.0 (C) Po ∝ Re 0.5 (D) Po ∝ Re 1.0

Last Answer : (B) Po ∝ Re 0.0 (C) Po ∝ Re 0.5

Power required to drive a ball mill with a particular ball load is proportional to (where, D = diameter of ball mill.) (A) D (B) 1/D (C) D2.5 (D) 1/D2.5

Description : Power required to drive a ball mill with a particular ball load is proportional to (where, D = diameter of ball mill.) (A) D (B) 1/D (C) D2.5 (D) 1/D2.5

Last Answer : (C) D2.5 (D) 1/D2

. Which of the following equations is Rittinger's crushing law? (Where P = power required by the machine, m = feed rate, k = a constant, Ds̅a & D̅sb = volume surface mean diameter of feed & product respectively.) (A) P/m = K/ √Dp (B) P/m = K . ln D̅sa /D̅sb (C) P/m = K . (1/ D̅sb - 1/Ds̅a ) (D) None of these

Description : . Which of the following equations is Rittinger's crushing law? (Where P = power required by the machine, m = feed rate, k = a constant, Ds̅a & D̅sb = volume surface mean diameter of feed & product respectively.) (A) P/m = K/ ... K . ln D̅sa /D̅sb (C) P/m = K . (1/ D̅sb - 1/Ds̅a ) (D) None of these

Last Answer : (C) P/m = K . (1/ D̅sb - 1/Ds̅a )

For 3.25 × 10-2 cumecs discharging from a well, a pump is installed to lift water against a total head of 30 m. The minimum required horse power, is (A) 10 H.P. (B) 15 H.P. (C) 18 H.P. (D) 20 H.P.

Description : For 3.25 × 10-2 cumecs discharging from a well, a pump is installed to lift water against a total head  of 30 m. The minimum required horse power, is  (A) 10 H.P.  (B) 15 H.P.  (C) 18 H.P.  (D) 20 H.P. 

Last Answer : (D) 20 H.P. 

A centrifugal pump is required to be primed before starting if it is located (A) At higher level than water level of reservoir (B) At lower level than water level of reservoir (C) Both (a) and (b) (D) Neither (a) nor (b)

Description : A centrifugal pump is required to be primed before starting if it is located  (A) At higher level than water level of reservoir  (B) At lower level than water level of reservoir  (C) Both (a) and (b)  (D) Neither (a) nor (b) 

Last Answer : (A) At higher level than water level of reservoir

The head developed by a centrifugal pump is largely determined by the (A) Power of the pump(B) Nature of the liquid being pumped(C) Angle of the vanes and the speed of the tip of the impeller(D) Vapour pressure of the liquid

Description : The head developed by a centrifugal pump is largely determined by the (A) Power of the pump (B) Nature of the liquid being pumped (C) Angle of the vanes and the speed of the tip of the impeller (D) Vapour pressure of the liquid

Last Answer : (C) Angle of the vanes and the speed of the tip of the impeller

The maximum depth from which a centrifugal pump can draw water is (A) Dependent on the speed of the pump (B) Dependent on the power of the pump (C) 34 feet (D) 150 feet

Description : The maximum depth from which a centrifugal pump can draw water is (A) Dependent on the speed of the pump (B) Dependent on the power of the pump (C) 34 feet (D) 150 feet

Last Answer : (C) 34 feet

A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump (A) Develops a lower head (B) Capacity is reduced (C) Requires more power (D) All (A), (B) and (C)

Description : A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump (A) Develops a lower head (B) Capacity is reduced (C) Requires more power (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

A centrifugal pump used to pump water is used to pump an oil withspecific gravity of 0.8 at the same rate. The power consumption will now (A) Increase (B) Decrease (C) Remain same (D) Data insufficient to predict

Description : A centrifugal pump used to pump water is used to pump an oil withspecific gravity of 0.8 at the same rate. The power consumption will now (A) Increase (B) Decrease (C) Remain same (D) Data insufficient to predict

Last Answer : (B) Decrease

The depth of the water table at a place is 45 m below the general ground level. To lift water from a deep tube well in such a locality, the type of pump to be installed is (A) Centrifugal pump (B) Reciprocating pump (C) Deep well turbine pump (D) None of these

Description : The depth of the water table at a place is 45 m below the general ground level. To lift water from a  deep tube well in such a locality, the type of pump to be installed is  (A) Centrifugal pump  (B) Reciprocating pump  (C) Deep well turbine pump  (D) None of these 

Last Answer : (C) Deep well turbine pump

The specific surface of spherical particles is proportional to (where, Dp = diameter of particle). (A) D2 p (B) Dp (C) 1/Dp (D) 1/D2p

Description : The specific surface of spherical particles is proportional to (where, Dp = diameter of particle). (A) D2 p (B) Dp (C) 1/Dp (D) 1/D2p

Last Answer : (C) 1/Dp

The angular momentum J of the electron in a hydrogen atom is proportional to `n^(th)` power of r (radius of the orbit) where n is :-

Description : The angular momentum J of the electron in a hydrogen atom is proportional to `n^(th)` power of r (radius of the orbit) where n is :-

Last Answer : The angular momentum J of the electron in a hydrogen atom is proportional to `n^(th)` power of r (radius of the orbit ... B. `-1` C. `(1)/(2)` D. None

Crude oil is pumped by a __________ pump. (A) Gear (B) Centrifugal

Description : Crude oil is pumped by a __________ pump. (A) Gear (B) Centrifugal

Last Answer : (B) Centrifugal

The type of pump used for the recirculation of molten sodium coolant in liquid metal cooled reactor is a/an __________ pump. (A) Electromagnetic (B) Reciprocating (C) Centrifugal (D) Volute

Description : The type of pump used for the recirculation of molten sodium coolant in liquid metal cooled reactor is a/an __________ pump. (A) Electromagnetic (B) Reciprocating (C) Centrifugal (D) Volute

Last Answer : (A) Electromagnetic

Centrifugal pump made of pyrex or glass can't be used to pump (A) Milk and fruit juices (B) Alkaline solutions (C) Dilute H2SO4 at room temperature (D) Brine

Description : Centrifugal pump made of pyrex or glass can't be used to pump (A) Milk and fruit juices (B) Alkaline solutions (C) Dilute H2SO4 at room temperature (D) Brine

Last Answer : (B) Alkaline solutions

For pumping slurry, one can use a __________ pump. (A) Reciprocating (B) Diaphragm (C) Centrifugal (D) Pneumatic

Description : For pumping slurry, one can use a __________ pump. (A) Reciprocating (B) Diaphragm (C) Centrifugal (D) Pneumatic

Last Answer : (B) Diaphragm

For the production of very high vacuum, a __________ pump is normally used. (A) Diffusion (B) Centrifugal (C) Jet ejector (D) Piston

Description : For the production of very high vacuum, a __________ pump is normally used. (A) Diffusion (B) Centrifugal (C) Jet ejector (D) Piston

Last Answer : (A) Diffusion

Liquid delivery by centrifugal pump starts, only when the head developed by it is equal to the __________ head. (A) Manometric (B) Total (C) Static (D) Friction

Description : Liquid delivery by centrifugal pump starts, only when the head developed by it is equal to the __________ head. (A) Manometric (B) Total (C) Static (D) Friction

Last Answer : (A) Manometric

Specific speed of a centrifugal pump depends upon the __________ head. (A) Suction (B) Delivery (C) Manometric (D) None of these

Description : Specific speed of a centrifugal pump depends upon the __________ head. (A) Suction (B) Delivery (C) Manometric (D) None of these

Last Answer : (D) None of these

Boiler feed water pump is usually a __________ pump.(A) Reciprocating (B) Gear (C) Multistage centrifugal (D) Diaphragm

Description : Boiler feed water pump is usually a __________ pump. (A) Reciprocating (B) Gear (C) Multistage centrifugal (D) Diaphragm

Last Answer : (C) Multistage centrifugal

While starting a centrifugal pump, its delivery valve should be kept (A) Opened (B) Closed (C) Either opened or closed; it does not make any difference (D) Either opened or closed; depending on the fluid viscosity

Description : While starting a centrifugal pump, its delivery valve should be kept (A) Opened (B) Closed (C) Either opened or closed; it does not make any difference (D) Either opened or closed; depending on the fluid viscosity

Last Answer : (B) Closed

Net positive suction head (NPSH) of a centrifugal pump must be (A) Greater than the vapour pressure of the liquid (B) Less than the vapour pressure of the liquid(C) Equal to the vapour pressure of the liquid(D) Less than barometric pressure

Description : Net positive suction head (NPSH) of a centrifugal pump must be (A) Greater than the vapour pressure of the liquid (B) Less than the vapour pressure of the liquid (C) Equal to the vapour pressure of the liquid (D) Less than barometric pressure

Last Answer : (A) Greater than the vapour pressure of the liquid

Volute type of casing is provided in a centrifugal pump to (A) Convert velocity head to pressure head (B) Convert pressure head to velocity head (C) Reduce the discharge fluctuation (D) Increase the discharge

Description : Volute type of casing is provided in a centrifugal pump to (A) Convert velocity head to pressure head (B) Convert pressure head to velocity head (C) Reduce the discharge fluctuation (D) Increase the discharge

Last Answer : (D) Increase the discharge

High specific speed of a pump implies that, it is a/an __________ pump. (A) Centrifugal (B) Mixed flow (C) Axial flow (D) None of these

Description : High specific speed of a pump implies that, it is a/an __________ pump. (A) Centrifugal (B) Mixed flow (C) Axial flow (D) None of these

Last Answer : (C) Axial flow

Draining of shallow pits or sump is done by a sump pump, which is a __________ pump. (A) Single stage vertical (B) Centrifugal (C) Plunger (D) Diffuser

Description : Draining of shallow pits or sump is done by a sump pump, which is a __________ pump. (A) Single stage vertical (B) Centrifugal (C) Plunger (D) Diffuser

Last Answer : (A) Single stage vertical

Maintenance cost of a __________ pump for a particular duty is the least. (A) Centrifugal (B) Reciprocating (C) Volute (D) Gear

Description : Maintenance cost of a __________ pump for a particular duty is the least. (A) Centrifugal (B) Reciprocating (C) Volute (D) Gear

Last Answer : (A) Centrifugal

Specific speed of a centrifugal pump relates it with another pump having the (A) Dynamic similarity (B) Same efficiency (C) Same speed (D) Geometrical similaritySpecific speed of a centrifugal pump relates it with another pump having the (A) Dynamic similarity (B) Same efficiency (C) Same speed (D) Geometrical similaritySpecific speed of a centrifugal pump relates it with another pumphaving the(A) Dynamic similarity(B) Same efficiency(C) Same speed(D) Geometrical similarity

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Last Answer : (A) Dynamic similarity

What causes cavitation in centrifugal pump? (A) High suction pressure (B) Low barometric pressure(C) Low suction pressure(D) High suction velocity

Description : What causes cavitation in centrifugal pump? (A) High suction pressure (B) Low barometric pressure (C) Low suction pressure (D) High suction velocity

Last Answer : (C) Low suction pressure

Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump? (A) Increasing the impeller speed and the volute area (B) Increasing the number of vanes in the impeller (C) Mounting of two or more impellers in series on a single shaft (D) Either of (A), (B) or (C)

Description : Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump? (A) Increasing the impeller speed and the volute area (B) Increasing the number of vanes ... or more impellers in series on a single shaft (D) Either of (A), (B) or (C)

Last Answer : (C) Mounting of two or more impellers in series on a single shaft

A centrifugal pump loses prime after starting. The reason of this trouble may be (A) Incomplete priming (B) Too high a suction lift (C) Low available NPSH and air leaks in the suction pipe (D) All (A), (B), and (C)

Description : A centrifugal pump loses prime after starting. The reason of this trouble may be (A) Incomplete priming (B) Too high a suction lift (C) Low available NPSH and air leaks in the suction pipe (D) All (A), (B), and (C)

Last Answer : (D) All (A), (B), and (C)

Priming of a centrifugal pump is done to (A) Increase the mass flow rate of fluid (B) Develop effective pressure rise by the pump (C) Avoid chances of separation inside the impeller (D) None of these

Description : Priming of a centrifugal pump is done to (A) Increase the mass flow rate of fluid (B) Develop effective pressure rise by the pump (C) Avoid chances of separation inside the impeller (D) None of these

Last Answer : (C) Avoid chances of separation inside the impeller

Various efficiencies of a centrifugal pump are related as (where, ηm = mechanical efficiency ηv = volumetric efficiency. ηma = manometric efficiency ηo = overall efficiency) (A) ηma × ηm × ηv = ηo (B) ηm = ηv . ηma (C) ηma = ηm × ηv (D) ηv = ηm × ηma

Description : Various efficiencies of a centrifugal pump are related as (where, ηm = mechanical efficiency ηv = volumetric efficiency. ηma = manometric efficiency ηo = overall efficiency) (A) ηma × ηm × ηv = ηo (B) ηm = ηv . ηma (C) ηma = ηm × ηv (D) ηv = ηm × ηma

Last Answer : (B) ηm = ηv . ηma