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Before World War II, some radios got power through a

College Physics | 1st Edition | ISBN: 9781938168000 | Authors: Paul Peter Urone, Roger Hinrichs ISBN: 9781938168000 42

Solution for problem 11CQ Chapter 21

College Physics | 1st Edition

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College Physics | 1st Edition | ISBN: 9781938168000 | Authors: Paul Peter Urone, Roger Hinrichs

College Physics | 1st Edition

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Problem 11CQ

Problem 11CQ

Before World War II, some radios got power through a “resistance cord” that had a significant resistance. Such a resistance cord reduces the voltage to a desired level for the radio’s tubes and the like, and it saves the expense of a transformer. Explain why resistance cords become warm and waste energy when the radio is on.

Step-by-Step Solution:
Step 1 of 3

Solution   11CQ

A transformer is a device used for step up or step down the voltage supply, to the desired value.

In this case, the voltage is desired to cut down to a level, matched to power up the radio set. So the resistance cord is used as supply cable as well as a device to cut down the voltage supply.

As the cord has a resistance of its own, so when the current pass through it, certain amount of voltage drop will be take place as,

V =I R

Here,  V is the voltage, I is the current and R is the resistance of the cord.

The charge q is the product of current I and time t.

Q = It

In a time interval t, a charge q goes through the cord , as the charge moves from one end to another the potential energy U due to this charge is decreased by,

U = qV

Here, U is loss in the potential energy, and q is the charge moved.

Substitute It for q and IR for V in above equation.

U  =(  It ) ( IR )

As energy is neither created nor destroyed, the loss in the potential energy is transformed into the thermal energy of the cord, and heats up the resistance cord and waste energy, when the radio set is on.

Step 2 of 3

Chapter 21, Problem 11CQ is Solved
Step 3 of 3

Textbook: College Physics
Edition: 1
Author: Paul Peter Urone, Roger Hinrichs
ISBN: 9781938168000

This textbook survival guide was created for the textbook: College Physics , edition: 1. Since the solution to 11CQ from 21 chapter was answered, more than 296 students have viewed the full step-by-step answer. The answer to “Before World War II, some radios got power through a “resistance cord” that had a significant resistance. Such a resistance cord reduces the voltage to a desired level for the radio’s tubes and the like, and it saves the expense of a transformer. Explain why resistance cords become warm and waste energy when the radio is on.” is broken down into a number of easy to follow steps, and 57 words. The full step-by-step solution to problem: 11CQ from chapter: 21 was answered by , our top Physics solution expert on 07/07/17, 04:39PM. College Physics was written by and is associated to the ISBN: 9781938168000. This full solution covers the following key subjects: resistance, cord, radio, radios, desired. This expansive textbook survival guide covers 34 chapters, and 3125 solutions.

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Before World War II, some radios got power through a