A step-down transformer connected to a 120 V electric generator has 30 loops on the primary for each loop in the secondary. (a) What is the voltage of the secondary? (b) If the transformer has a 90.0 A current in the primary, what is the current in the secondary? (c) What are the power input and output?
(a)
The secondary voltage of a step-down transformer.
Answer to Problem 16PEB
Solution:
The secondary voltage is
Explanation of Solution
Given data:
A step-downtransformer with 30 loops for every loop at the primary side. The primary coil is supplied with
Formula used:
The expression that relates the number of loops and the voltage is written as,
Here,
Explanation:
Consider the expression.
Rearrange to get the secondary voltage
The number of loops at the primary and the secondary sides are dependent on each other.
Consider theloops at secondary side be
Substitute
Conclusion:
Hence, the secondary voltage is
(b)
The secondary current in the step-down transformer.
Answer to Problem 16PEB
Solution:
The secondary current is
Explanation of Solution
Given data:
A step-down transformer with 30 loops for every loop at the primary side. The primary coil is supplied with
Formula used:
The expression for power in a transformer is written as,
Here,
Explanation:
Consider the expression for power in the transformer.
Rearrange the power expression to get the secondary current
Substitute
Conclusion:
Hence, the current at the secondary side is
(c)
The power of the transformer at the input and the output sides.
Answer to Problem 16PEB
Solution:
The power at the input and the output side is same and is equal to
Explanation of Solution
Given data:
A step-down transformer with 30 loops for every loop at the primary side. The primary coil is supplied with
Formula used:
The expression for power at the input side is written as,
Here,
The expression for power at the output side is written as,
Here,
Explanation:
Consider the expression for the input power.
Substitute
Similarly, consider the expression for the output power.
Substitute
Conclusion:
Hence, the power at the input and the output side is same and is equal to
Want to see more full solutions like this?
Chapter 6 Solutions
Package: Loose Leaf Physical Science With Connect Access Card
- A 120-V, series-wound dc motor draws 0.50 A from its power source when operating at full speed, and it draws 2.0 A when it starts. The resistance of the armature coils is 10 , (a) What is the resistance of the field coils? (b) What is tire back emf of the motor when it is running at full speed? (c) The motor operates at a different speed and draws 1.0 A from the source. What is the back emf in this case?arrow_forwardA coil with 50 turns and area 10cm2 is oriented with its plane perpendicular to a 0.75-T magnetic field. If the coil is flipped over (rotated through 180°) in 0.20 s, what is the average emf induced in it?arrow_forwardSuppose that a rectangular toroid has 2000 windings and a self-inductance of 0.040 H. If h = 0.10 m, what is the current flowing through a rectangular toroid when the energy in its magnetic field is 2.0 × 10-6 J?arrow_forward
- Will a transformer work if the input is a dc voltage?arrow_forwardAn emf of 9.7 × 10-3 V is induced in a coil while the current in a nearby coil is decreasing at a rate of 2.7 A/s. What is the mutual inductance of the two coils?arrow_forwardAn emf of 0.40 V is induced across a coil when the current through it changes uniformly from 0.10 to 0.60 A in 0.30 s. What is the self-inductance of the coil?arrow_forward
- A toroidal coil has a mean radius of 16 cm and a cross-sectional area of 0.25 cm2; it is wound uniformly with 1000 turns. A second toroidal coil of 750 turns is wound uniformly over the first coil. Ignoring the variation of the magnetic field within a toroid, determine the mutual inductance of the two coils.arrow_forwardA generator spinning at a rate of 1.20 103 rev/min produces a maximum emf of 45.0 V. At what angular speed does this generator produce a maximum emf of 64.0 V?arrow_forwardWhen the current through a large inductor is interrupted with a switch, an are appears across the open terminals of the switch. Explain.arrow_forward
- Does the induced emf always act to decrease the magnetic flux through a circuit?arrow_forwardSuppose a large power plant generates electricity at 12.0 kV. Its old transformer once converted this voltage to 360 kV. The secondary coil of this transformer is being replaced so that its output can be 740 kV for more efficient cross-country transmission on upgraded transmission lines. If the overall power output is 1000.0 MW and line resistance is 2.00 Ω, what is the power loss, in watts, in the new power lines which leave the plant?arrow_forwardA power transmission line feeds input power at 2300 V to a stepdown transformer with its primary windings having 4000 turns. What should be the number of turns in the secondary in order to get output power at 230 V?arrow_forward
- Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
- Physics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning