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A transformer of efficiency 90% draws an input power of 4 kW. An electrical appliance connected across the secondary draws a current of 6 A. The impedance of the device is
a)60 Ω
b)50 Ω
c)80 Ω
d)100 Ω
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Verified Answer
A transformer of efficiency 90% draws an input power of 4 kW. An elect...
Efficiency, η = Po/Pi with usual notations. Therefore, the output power is given by
Po = η Pi = 0.9 ×4000 W = 3600 W.
In the problem nothing is mentioned about the power factor cos φ. At your level the load is usually assumed to be effectively resistive so that the power factor may be assumed to be unity. Therefore we have
Po = Io2R where R is the load resistance (or, the load impedence in this case).
This gives R = Po /Io2 = 3600 /62 = 100 Ω.
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A transformer of efficiency 90% draws an input power of 4 kW. An elect...
Solution:
Given data:
Efficiency of transformer, η = 90% = 0.9
Input power, P1 = 4 kW
Current drawn by the electrical appliance, I2 = 6 A
To find: Impedance of the device, Z2
We know that,
Efficiency of transformer, η = Output power / Input power
Or, Output power = η x Input power
Or, P2 = 0.9 x 4 kW
Or, P2 = 3.6 kW
We also know that,
Output power, P2 = V2 x I2
Therefore,
V2 = P2 / I2
Or, V2 = 3.6 kW / 6 A
Or, V2 = 600 V
Now,
Impedance of the device, Z2 = V2 / I2
Or, Z2 = 600 V / 6 A
Or, Z2 = 100 Ω
Therefore, the impedance of the device is 100 Ω.
Answer: (d) 100 Ω
Given data:
Efficiency of transformer, η = 90% = 0.9
Input power, P1 = 4 kW
Current drawn by the electrical appliance, I2 = 6 A
To find: Impedance of the device, Z2
We know that,
Efficiency of transformer, η = Output power / Input power
Or, Output power = η x Input power
Or, P2 = 0.9 x 4 kW
Or, P2 = 3.6 kW
We also know that,
Output power, P2 = V2 x I2
Therefore,
V2 = P2 / I2
Or, V2 = 3.6 kW / 6 A
Or, V2 = 600 V
Now,
Impedance of the device, Z2 = V2 / I2
Or, Z2 = 600 V / 6 A
Or, Z2 = 100 Ω
Therefore, the impedance of the device is 100 Ω.
Answer: (d) 100 Ω
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A transformer of efficiency 90% draws an input power of 4 kW. An electrical appliance connected across the secondary draws a current of 6 A. The impedance of the device isa)60Ωb)50Ωc)80Ωd)100Ω for NEET 2024 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about A transformer of efficiency 90% draws an input power of 4 kW. An electrical appliance connected across the secondary draws a current of 6 A. The impedance of the device isa)60Ωb)50Ωc)80Ωd)100Ω covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A transformer of efficiency 90% draws an input power of 4 kW. An electrical appliance connected across the secondary draws a current of 6 A. The impedance of the device isa)60Ωb)50Ωc)80Ωd)100Ω.
A transformer of efficiency 90% draws an input power of 4 kW. An electrical appliance connected across the secondary draws a current of 6 A. The impedance of the device isa)60Ωb)50Ωc)80Ωd)100Ω for NEET 2024 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about A transformer of efficiency 90% draws an input power of 4 kW. An electrical appliance connected across the secondary draws a current of 6 A. The impedance of the device isa)60Ωb)50Ωc)80Ωd)100Ω covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A transformer of efficiency 90% draws an input power of 4 kW. An electrical appliance connected across the secondary draws a current of 6 A. The impedance of the device isa)60Ωb)50Ωc)80Ωd)100Ω.
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