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What will happen if the transformers working in parallel are not connected with regard to polarity ?
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asked
Mar 19, 2018
by
anonymous
transformers
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answered
Mar 19, 2018
by
anonymous
Incorrect polarity will result in dead short circuit.
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May 18, 2019
by
prasadnani
Winding will be damaged
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Related questions
asked
Mar 19, 2018
by
anonymous
If the percentage impedances of the two transformers working in parallel are different, then?
Last answer:
If the percentage impedances of the two transformers working in parallel are different, then parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load.
transformers
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57
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1
answer
asked
Mar 19, 2018
by
anonymous
Losses which occur in rotating electric machines and do not occur in transformers are?
Losses which occur in rotating electric machines and do not occur in transformers are?
Last answer:
Friction losses windage losses
losses
rotating
electric
machines
transformers
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108
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2
answers
asked
May 8, 2018
by
anonymous
In a transmission line if booster transformers are to be used, preferred location will be
In a transmission line if booster transformers are to be used, preferred location will be (A) At the receiving end (B) At the sending end (C) At the intermediate point (D) Anywhere in the line
Last answer:
In a transmission line if booster transformers are to be used, preferred location will be At the intermediate point
transmission
line
booster
transformers
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1
answer
asked
Mar 19, 2018
by
anonymous
Two transformers do not have equal percentage impedance. This is likely to result in?
Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in?
Last answer:
Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in loading of the transformers not in proportion to their kVA ratings.
transformers
parallel
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asked
Mar 19, 2018
by
anonymous
For the parallel operation of single phase transformers it is necessary that they should have?
Last answer:
Necessary conditions required to be satisfied in order to ensure successful parallel operation of single phase transformers: 1. Only transformers having the same phase displacement between primary and secondary ... . 7. The phase sequence must be followed strictly on HV and LV side connection.
parallel
operation
single
phase
transformers
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2
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asked
Mar 19, 2018
by
anonymous
The efficiencies of transformers compared with that of electric motors of the same power are?
The efficiencies of transformers compared with that of electric motors of the same power are?
Last answer:
Transformers have high efficiency than the same ratted motors
efficiencies
transformers
electric
motors
power
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2
answers
asked
Apr 30, 2018
by
anonymous
Two 3-phase transformers cannot be operated in parallel, if their :
Two 3-phase transformers cannot be operated in parallel, if their : (A) kVAs are different (B) phase sequences are different (C) % impedances are different (D) voltage ratios are different
Last answer:
Two 3-phase transformers cannot be operated in parallel, if their : phase sequences are different
3-phase
transformers
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1
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asked
Mar 19, 2018
by
anonymous
Power transformers are generally designed to have maximum efficiency around?
Last answer:
Power transformers are generally designed to have maximum efficiency around near full-load.
transformers
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asked
May 22, 2018
by
anonymous
Two transformers with identical voltage ratings are working in parallel to supply common load. The percentage
Two transformers with identical voltage ratings are working in parallel to supply common load. The percentage impedance of one transformer is higher compared to that of other. The load sharing between the two transformer will: (1) Be proportional to their percentage impedance (2) Be independent of their percentage impedance (3) Be inversely proportional of their respective impedance (4) Depend on the resistance to leakage reactance ratio of each transformer
Last answer:
Two transformers with identical voltage ratings are working in parallel to supply common load. The percentage impedance of one transformer is higher compared to that of other. The load sharing between the two transformer will: Be inversely proportional of their respective impedance
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asked
Mar 19, 2018
by
anonymous
Distribution transformers are generally designed for maximum efficiency around?
Last answer:
Distribution transformers are generally designed for maximum efficiency around 50% load.
transformers
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1
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asked
Mar 19, 2018
by
anonymous
Natural oil cooling is used for transformers up to a rating of?
Last answer:
Natural oil cooling is used for transformers up to a rating of 3000 kVA.
transformers
cooling
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1
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asked
Mar 19, 2018
by
anonymous
Short circuit test on transformers is conducted to determine?
Last answer:
Short circuit test on transformers is conducted to determine copper losses.
short
circuit
test
transformers
conducted
determine
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asked
Mar 19, 2018
by
anonymous
Natural air cooling is generally restricted for transformers up to?
Last answer:
Natural air cooling is generally restricted for transformers up to 1.5 MVA .
natural
air
cooling
restricted
transformers
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1
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asked
Sep 18, 2017
by
anonymous
What will happen when capacitors are connected in parallel?
Last answer:
The capacity of capacitor is added and it becomes multiple of no of capacitors capacity
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asked
Jan 15, 2018
by
James
of what use are current and voltage transformers in protective systems
Last answer:
Current transformers (CT) : Current transformer (CT) actually step down the high current to low current for the operation of relays. Current transformer is use for measurement of ... use for relay. This is about potential transformer.
relay-
transformers
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1
answer
asked
Mar 19, 2018
by
anonymous
The efficiency of two identical transformers under load conditions can be determined by?
The efficiency of two identical transformers under load conditions can be determined by?
Last answer:
The efficiency of two identical transformers under load conditions can be determined by back-to-back test.
efficiency
identical
transformers
load
conditions
determined
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113
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1
answer
asked
Apr 29, 2018
by
anonymous
An additional condition for parallel operation of three-phase transformers over single-phase transformers is that
An additional condition for parallel operation of three-phase transformers over single-phase transformers is that
Last answer:
An additional condition for parallel operation of three-phase transformers over single-phase transformers is that the transformers should belong to the same vector group
parallel
operation
three-phase
transformers
single-phase
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asked
Jun 4, 2018
by
anonymous
If two 3-phase transformers with unequal voltage ratios are connected in parallel, the result is
If two 3-phase transformers with unequal voltage ratios are connected in parallel, the result is (A) circulating current on no-load (B) no circulating current on no-load (C) dead short-circuit (D) equal no-load secondary emfs
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answers
asked
May 8, 2018
by
anonymous
Which of the following connection of transformers will give highest value of secondary voltage ?
Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary
Last answer:
Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary
connection
transformers
highest
value
secondary
voltage
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1
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asked
May 8, 2018
by
anonymous
The friction losses in Real Transformers are :
The friction losses in Real Transformers are : (A) 0% (B) 5% (C) 25% (D) 50%
Last answer:
A
friction
losses
real
transformers
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2
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asked
Mar 15, 2018
by
anonymous
What is the back EMF in Transformers?
What is the back EMF in Transformers?
back
emf
transformers
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asked
May 8, 2018
by
anonymous
What will happen if the primary of a transformer is connected to D.C. supply?
What will happen if the primary of a transformer is connected to D.C. supply? (A) Transformer will operate with low efficiency (B) Transformer will operate with high efficiency (C) No effect (D) Transformer may start to smoke and burn
Last answer:
What will happen if the primary of a transformer is connected to D.C. supply? (A) Transformer will operate with low efficiency (B) Transformer will operate with high efficiency (C) No effect (D) Transformer may start to smoke and burn
transformer
dc
supply
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1
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asked
Apr 12, 2018
by
anonymous
If a cell connection is reversed in parallel group, what will happen?
If a cell connection is reversed in parallel group, what will happen? A. Open circuit B. All cells will be equally charged C. short circuit D. Nothing will happen
Last answer:
If a cell connection is reversed in parallel group, what will happen? Open circuit
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106
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1
answer
asked
May 8, 2018
by
anonymous
Core type transformers are popular in___________.
Core type transformers are popular in___________. (A) High voltage applications (B) Low voltage applications (C) All of the above (D) None of the above
Last answer:
Core type transformers are popular in High voltage applications
core
type
transformers
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55
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1
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asked
Mar 21, 2018
by
anonymous
Instrument transformers are?
Last answer:
Instrument transformers are potential transformers, current transformers.
instrument
transformers
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1
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asked
May 26, 2018
by
anonymous
What will happen if a voltmeter is connected like an ammeter in series of the load ?
What will happen if a voltmeter is connected like an ammeter in series of the load ? (a) The meter will burn out. (b) The measurement will be too high. (c) The same current will flow as would have been with ammeter in circuit. (d) There will be almost no current in the circuit.
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75
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0
answers
asked
May 12, 2018
by
anonymous
Which of the following will happen if a voltmeter is connected like an ammeter in series to the
Which of the following will happen if a voltmeter is connected like an ammeter in series to the load ? (A) There will be almost no current in the circuit. (B) The meter will burn. (C) The measurement will be trio high. (D) A very high current will flow.
Last answer:
Which of the following will happen if a voltmeter is connected like an ammeter in series to the load ? (A) There will be almost no current in the circuit. (B) The meter will burn. (C) The measurement will be trio high. (D) A very high current will flow.
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1
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asked
May 17, 2018
by
anonymous
Two transformers are to be operated in parallel such that they share load in proportion to their kVA ratings.
Two transformers are to be operated in parallel such that they share load in proportion to their kVA ratings. The rating of the first transformer is 500 kVA ratings. The rating of the first transformer is 500 kVA and its pu leakage impedance is 0.05 pu. If the rating of second transformer is 250 kVA, its pu leakage impedance is (A) 0.20 (B) 0.10 (C) 0.05 (D) 0.025
Last answer:
Two transformers are to be operated in parallel such that they share load in proportion to their kVA ratings. The rating of the first transformer is 500 kVA ratings. The rating of the first transformer is ... .05 pu. If the rating of second transformer is 250 kVA, its pu leakage impedance is 0.10
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158
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1
answer
asked
May 12, 2018
by
anonymous
Two transformers operating in parallel will share the load depending upon their
Two transformers operating in parallel will share the load depending upon their
Last answer:
Two transformers operating in parallel will share the load depending upon their Per unit impedance
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200
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1
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asked
Aug 13, 2019
by
Alacrity
the volt per turn of a certain single phase transformers is 1.7. the transformer has a step ratio of 3825/255volt. calculate the respective number of turns in each winding
single
phase
transformers
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asked
Apr 29, 2018
by
anonymous
Which of the following is the advantage of using CRGO steel in transformers?
Which of the following is the advantage of using CRGO steel in transformers? A) High magnetic flux density B) Low permeability C) Both A and B D) None of these
Last answer:
It definitely High Magnetic Flux Density since a crgo steel has always a more around 3% of silicon proportion among the remaining ferrite which make cold rolled grain oriented steel having high flux magnetic ... for more about the crgo core you can learn here https://nicoreindia.com/crgo-core/
crgo
steel
transformers
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81
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2
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asked
Aug 30, 2018
by
anonymous
Classify the transformers based on the construction, frequency and power.
Classify the transformers based on the construction, frequency and power.
Last answer:
Classification of Transformer Based On: i) Construction: Shell type, Core type, Berry type ii) Change in voltage level: Step-Up, Step-Down, iii) Number of phases: Single phase, Three phase iv) ... Control vi) Cooling: Self-cooled, Air-cooled, Forced-air cooled, Oil-cooled, Forced-oil cooled.
classify
transformers
construction
frequency
power
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105
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1
answer
asked
May 8, 2018
by
anonymous
Two transformers A and B having equal outputs and voltage ratios but unequal percentage
Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. The transformer A will be overloaded by
Last answer:
Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. The transformer A will be overloaded by 33%
transformers
voltage
ratios
percentage
impedances
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201
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1
answer
asked
Dec 17, 2017
by
anonymous
Why do transformers make noise?
Why do transformers make noise?
Last answer:
Transformers make noise based on it out put if an transformer outputs is 400v maximum than a 398v be apply to that transformer it also make a noise because of that
transformers
noise
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72
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1
answer
asked
Mar 19, 2018
by
anonymous
Harmonics in transformer result in?
Last answer:
Harmonics in transformer result in increased core losses, increased I2R losses, and magnetic interference with communication circuits.
transformers
harmonics
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1
answer
asked
Apr 12, 2018
by
anonymous
Three lamps are connected in parallel across a 120 Volt source. If one lamp burns out, the remaining two will ...
Three lamps are connected in parallel across a 120 Volt source. If one lamp burns out, the remaining two will be: A. Glow dimmer B. Glow brighter C. Not light D. Glow with the same brightness as before
Last answer:
Glow with the same brightness as before
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2.6k
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2
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asked
May 25, 2018
by
anonymous
Three single phase transformers each with 10 kVA rating are connected in a closed delta arrangement. If one
Three single phase transformers each with 10 kVA rating are connected in a closed delta arrangement. If one transformer is taken out, the output capacity of the system will be (a) 20 kVA (b) 8.66 kVA (c) 17.32 kVA (d) 10 kVA
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0
answers
asked
May 22, 2018
by
anonymous
When two transformer of different kVA rating are connected in parallel they share the load in proportion to
When two transformer of different kVA rating are connected in parallel they share the load in proportion to their respective kVA rating only when their:
Last answer:
When two transformer of different kVA rating are connected in parallel they share the load in proportion to their respective kVA rating only when their: P u impedance are equal
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179
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1
answer
asked
Dec 11, 2017
by
anonymous
what will be the capacitance if three capacitors connected in parallel each having value of 0.5 micro Farad ?
what will be the capacitance if three capacitors connected in parallel each having value of 0.5 micro Farad ?
Last answer:
the total capacitace when connected in parallel Tc=total capacitor c1=c2=c3=0.5uf Tc=c1+c2+c3 Tc=1.5uf
problem
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3
answers
asked
May 8, 2018
by
anonymous
What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to
What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage: (A) Eddy Current and Hysteresis losses will be excessive (B) Current will be too much high (C) Transformer may start to smoke and burn (D) No effect
Last answer:
What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage: (A) Eddy Current and Hysteresis losses will be ... will be too much high (C) Transformer may start to smoke and burn (D) No effect
power
transformer
designed
operation
frequency
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499
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1
answer
asked
Jan 8
by
anonymous
State any two conditions for parallel operation of 3-phase transformer.
State any two conditions for parallel operation of 3-phase transformer.
Last answer:
Conditions for Parallel operation of 3 phase transformer 1) Voltage ratings of both the transformers must be identical. 2) Percentage or p.u. impedance should be equal in magnitude. 3) X/R ratio ... between primary & secondary voltages must be same. 6) Phase sequence on both sides must be same.
dc
machines
transformers
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7
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1
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asked
Mar 19, 2018
by
anonymous
A common method of cooling a power transformer is?
Last answer:
A common method of cooling a power transformer is oil cooling.
transformers
cooling
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75
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1
answer
asked
Jun 18, 2018
by
anonymous
What will happen to the gain margin if the gain of the open loop system is doubled?
What will happen to the gain margin if the gain of the open loop system is doubled? A) Doubled B) Becomes half C) Is not affected D) Becomes one-fourth
Last answer:
What will happen to the gain margin if the gain of the open loop system is doubled? A) Doubled B) Becomes half C) Is not affected D) Becomes one-fourth
gain
margin
open
loop
system
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146
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1
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asked
5 days
ago
by
anonymous
A metal plate with a circular hole at the centre is heated. What will happen to the area of the hole ? (1) Increase (2) Dacrease (3) Remain constant (4) Will increase first and then dcrease
A metal plate with a circular hole at the centre is heated. What will happen to the area of the hole ? (1) Increase (2) Dacrease (3) Remain constant (4) Will increase first and then dcrease
Last answer:
Increase
physics
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asked
Mar 15, 2018
by
anonymous
What will happen if you increase the current in the motor?
What will happen if you increase the current in the motor?
Last answer:
Increasing current means increasing frequency of the motor because current is directly proportional to rotations of the motor rotor
increase
current
motor
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143
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1
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asked
Apr 25, 2018
by
anonymous
If a positively charged body is placed inside a spherical hollow conductor, what will be the polarity of charge...
If a positively charged body is placed inside a spherical hollow conductor, what will be the polarity of charge inside and outside the hollow conductor ? (a) Inside positive, outside negative (b) Inside negative, outside positive (c) Both negative (d) Both positive
Last answer:
The polarity of the charge will positive
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249
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2
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asked
Jan 12
by
anonymous
A task is done by 46 persons not all of them have the same capacity to task. Every day exactly 2 persons, do the task with no pair of persons working together twice. Even after all possible pairs have worked once, all the persons together works for two more days to finish the task. Find the number of days in which all the persons together will finish the whole task? a) 44 b) 45 c) 46 d) 47
A task is done by 46 persons not all of them have the same capacity to task. Every day exactly 2 persons, do the task with no pair of persons working together twice. Even after all possible pairs have worked once, all the persons together works for two more days to finish the task. Find the number of days in which all the persons together will finish the whole task? a) 44 b) 45 c) 46 d) 47
Last answer:
D 46 persons task in pairs, with no same pair of persons working together. Each person will be working with other 45 which means each persons will work for 45 days in pair. Let the time taken by each ... +1/T46)= 1/47 If all the persons work together they will finish the whole task in 47 days.
time-and-work
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11
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1
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asked
Apr 25, 2018
by
anonymous
Two transformers having the same p.u. impedance connected in parallel share the connected load
Two transformers having the same p.u. impedance connected in parallel share the connected load (A) equally (B) in proportion to the respective ratings (C) in proportion to the voltage ratio (D) in proportion to the zero phase displacement
Last answer:
Two transformers having the same p.u. impedance connected in parallel share the connected load in proportion to the respective ratings
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81
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1
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asked
4 days
ago
by
anonymous
A wire of resistance R is cut into ‘n’ equal parts. These parts are then connected in parallel. The equivalent resistance of the combination will be
A wire of resistance R is cut into ‘n’ equal parts. These parts are then connected in parallel. The equivalent resistance of the combination will be
Last answer:
R/n2
physics
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asked
May 29, 2018
by
anonymous
How will the total capacitance change, when two capacitors are connected in parallel?
How will the total capacitance change, when two capacitors are connected in parallel?
Last answer:
The capacitance will increase if connected in parallel because it will be like you have increase surface area of a plate by connecting it to another.
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