# The efficiency of a centrifugal pump is maximum when its blades are :

8 views
The efficiency of a centrifugal pump is maximum when its blades are : (A) straight (B) bent forward (C) bent backward (D) bent forward first and then backward

The efficiency of a centrifugal pump is maximum when its blades are : bent backward

## Related questions

Power transmitted through a pipe is maximum when the loss of head due to friction is : (A) one-half of the total head supplied (B) one-third of the total head supplied (C) one-fourth of the total head supplied (D) zero

A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -  a) 16/9 b) 4 / 3 c) 3/4 d) 9 /16

When a source is delivering maximum power to a load, the efficiency of the circuit is always (a) 50% (b) 75% (c) 100% (d) Depends on the circuit parameters

When The dc converter in figure shown has a resistance load of R = 10 Ω and the input voltage is Vs 220 V the converter switch remains on, its voltage drop is Vo -2 V. The chopping frequency is fI K sW Vs If the duty cycle is 50%, determine: (a) the average output voltage V (b) the RMS output voltage Vo (c) the converter efficiency (d) the effective input resistance of the converter

If X is the system reactance and R is its resistance, the power transferred is maximum when (1) X=R (2) X=1.414 R (3) X=1.732 R (4) X=2R

At maximum efficiency of a single-phase transformer, the load power factor is (A) unity (B) lagging (C) leading (D) zero

What happens to the resistance of a wire when its length as well as the cross-sectional area are doubled? A) It doubles B) It becomes 4 times C) It becomes 2π times D) It remains the same

The ratio of maximum displacement of the forced vibration to the deflection due to static force is known as : (A) Damping Factor (B) Damping Coefficient (C) Logarithmic Decrement (D) Magnification Factor

The efficiency of a transformer at full load 0.8 p.f lagging is 90%. Its efficiency at full load 0.8 p.f leading will be (1) Less than 90% (2) More than 90% (3) 90% (4) None of these

Which of the following units is connected with discharge in a domestic water pump?  A) Kg/SqCm B) RPM C) LPM D) N/m2

The output of logic gate is '1' when all its inputs are at logic '0' The gate is (A) NAND/EX-OR (B) NOR/EX-OR (C) AND/EX-NOR (D) NOR/EX-NOR

The maximum transmission power efficiency of DSB-C Amplitude modulation is : a. 25% b. 33.33% c. 50% d. 100%

A power supply produces a 0.6 W output with an input of 0.7 W. Its percentage of efficiency is: A. 8.57% B. 42.85% C. 4.28% D. 85.7%

The probability of a photon ionizing an atom or molecule is maximum when (hv-eVi) is as small as: a. 0.5 b. 1.5 c. 3.5 d. 10

The effect of stray magnetic fields on the actuating torque of a portable instrument is maximum when the operating field of the instrument and the stray fields are  A) Perpendicular B) Parallel C) Inclined at 60" D) Inclined at 30°

When a dipole antenna of 1/8 length has an equivalent total resistance of 1.5 Watt then the efficiency of the antenna is   (A) 0.89159% (B) 8.9159% (C) 89.159% (D) 891.59%

A 150 kW electric motor has an efficiency of 92 %, when it operates at full load. Calculate the losses in the machine.  (A) 92 kW (B) 150 kW (C) 163 kW (D) 13 kW

A simple phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor is  (A) 86.7% (B) 88.26% (C) 88.9% (D) 87.8%

Transformer voltage is maximum when two coils are (1) Normal to each other (2) Aligned along the same axis (3) 600 away from each other (4) 2700 away from each other

If modulation index is 0.6, maximum power efficiency (in %) of AM is about  A) 60 B) 30 C) 20 D) 10

The o/p of a 2 - input OR gate is 1 when its   1. both inputs are 1 2. both inputs are 0 3.either input is 1 4. either input is 0

When the temperature of a doped semiconductor is increased, its conductivity  (1) Decreases (2) Increases (3) Does not change (4) Increases or decreases depending on whether it is p-type or n-type

The maximum load that a power transformer can carry is limited by its?

Define efficiency of a transformer. State its formula.

A transformer operates 24 hours day at full -load. It's full -load efficiency is :  (A) equal all day efficiency (B) more than all -day efficiency (C) less than all -day efficiency (D) equal to maximum efficiency

A 1-phase, 7.46 kW motor is supplied from a 400 V, 50 Hz A.C mains. Its efficiency is 85% and power factor is 0.8 lagging. Calculate the KVA input (1) 9.56 kVA (2) 5.4 Kva (3) 10.97 kVA (4) 8.6 kVA

Two waves have frequency of 500 Hz. One is set at its maximum value whereas the other at zero. The phase angle between them will be

The maximum demand of consumer is 2 kW and his daily energy consumption is 20 units. Its Load Factor is (1) 10.15% (2) 41.6 % (3) 50 % (4) 60%

Ripple in output current of a step-down chopper feeding RLE load is maximum, when duty cycle is equal to:  (1) 1 (2) 0.5 (3) 0.75 (4) 0.33

In a PCM system the number of quantization level are 16 and the maximum signal frequency is 4 KHz the transmission bit rate is

The maximum flux in a transformer is φm when primary voltage is V and the frequency is f. If the primary voltage is 2 V and frequency is f/2, the flux will be (a) 4 φm (b) 0.25 φm (c) φm (d) 0.5 φm

In class - A power amplifier, the collector dissipation is maximum when  (a) no signal is present  (b) signal swing is maximum  (c) signal swing is (1/1.414) of its maximum  (d) none of the above

The maximum power in a synchronous motor (for a given excitation) is produced when the power angle is equal to: (A) 0° (B) 45° (C) 60° (D) 90°

"Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load". The above statement is associated with?