Physics 121 Practice Problem Solutions 07 Current and Resistance

Slides:

Advertisements

Similar presentations

Have you ever held a wire that has current flowing through it? If so what did you notice about it? The wire gets hot. The increase in temperature causes.

Advertisements

Fisica Generale - Alan Giambattista, Betty McCarty Richardson Copyright © 2008 – The McGraw-Hill Companies s.r.l. 1 Chapter 18: Electric Current and Circuits.

Physics Review #1 LCHS Dr.E. A positive test charge is placed between an electron, e, and a proton, p, as shown in the diagram below. When the test charge.

Current. Current Current is defined as the flow of positive charge. Current is defined as the flow of positive charge. I = Q/t I = Q/t I: current in Amperes.

Electric Currents and Resistance

Resistance. Definition Opposition to the flow of electrons When electrons pass through materials with high resistance, they collide with its molecules.

Current and Resistance FCI.  Define the current.  Understand the microscopic description of current.  Discuss the rat at which the power.

Chapter 27: Current and Resistance Reading assignment: Chapter 27 Homework 27.1, due Wednesday, March 4: OQ1, 5, 14 Homework 27.2, due Friday, March 6:

Current and Resistance JH

Chap-26: Current and Resistance In the last five chapters we discussed electrostatics—the physics of stationary charges. In this and the next chapter,

Chapter 17 Current and Resistance. Electric Current Let us look at the charges flowing perpendicularly to a surface of area A The electric current is.

DC Circuit Overview Examination #2 Review March 1, 2010 ?

Electric circuit power, circuit elements and series-parallel connections.

Current and Resistance

Electric Circuits Count Alessandro Volta ( ) André Marie AMPÈRE ( ) Charles Augustin de Coulomb (1736 – 1806) Georg Simon Ohm (1787.

7/1/20151 T. Norah Ali Al-Moneef King Saud unvercity.

Announcements Master of Exam I is available in E-learning. The scores will be posted soon. Class average of and standard deviation 3.42 QUESTIONS?

RESISTANCE – OHM’S LAW Lesson 5. Resistance  The amount of current flow in a circuit, and the amount of energy transferred to any useful device, depends.

Electric Currents and Resistance

Electric Current. Answer Me!!!  Why are electric wires made from metal?

My Chapter 18 Lecture Outline.

Lecture 12 Current & Resistance (2)

Current. Current Current is defined as the flow of positive charge. Current is defined as the flow of positive charge. I = Q/t I = Q/t I: current in Amperes.

University Physics: Waves and Electricity Ch26. Ohm’s Law Lecture 10 Dr.-Ing. Erwin Sitompul

123 What do the following terms mean? Current Resistance Parallel Circuit Series Circuit.

Do Now What work is required to move 7 coulombs of charge through a potential difference of 3 volts?

Electric Circuits.

Current, Resistance and Power

Chapter 17 Current and Resistance. Electric Current Let us look at the charges flowing perpendicularly to a surface of area A The electric current is.

Copyright © 2009 Pearson Education, Inc. Lecture 6: Electric Currents & Resistance.

 I1I1   R R R I2I2 I3I3 Lecture 11 Current & Resistance.

 Basic Electricity Chapter 17. Battery  A battery converts stored chemical potential energy into electrical energy.  A battery consist of two unlike.

Physics Review #1 LCHS Dr.E. What is the voltage? 12Ω 36V 6Ω 2Ω 2Ω.

Lecture 17 Problems & Solution(1). [1] What is the magnitude of the current flowing in the circuit shown in Fig. 2? [2] A copper wire has resistance 5.

Dr. Jie ZouPHY Chapter 21 Electric Current and Direct- Current Circuits.

Current and Resistance

Current Electric Current (I)

Electric Current and Resistance Chapter 19 Sections 1 & 2.

Chapter 27 Current and Resistance Scalar Sense determined by the movement of the positive charge carrier Average Electric Current Instantaneous Electric.

110/26/2015 General Physics (PHY 2140) Lecture 9  Electrodynamics Electric current temperature variation of resistance electrical energy and power Chpter.

CLASS :- X MADE BY :- MANAS MAHAJAN SCHOOL :- K.V. GANESHKHIND PUNE-7

Physics 1202: Lecture 7 Today’s Agenda Announcements: –Lectures posted on: –HW assignments, solutions.

Current of Electricity Electric Current Potential Difference Resistance and Resistivity Electromotive Force.

AQA AS ElectricityUnit 1Name_____________ Question 1. (a)Describe the motion of the free charge carriers in a current-carrying wire. (3 marks) (b)A current.

ElectricityName_____________ Question 1. (a)Describe the motion of the free charge carriers in a current-carrying wire. (3 marks) charge carriers = (free)

Electric Currents AP Physics Chapter 18. Electric Currents 18.1 The Electric Battery.

Physics 212 Lecture 9, Slide 1 Physics 212 Lecture 9 Today's Concept: Electric Current Ohm’s Law & resistors Resistors in circuits Power in circuits.

20.1 Electromotive Force and Current Example 1 A Pocket Calculator The current in a 3.0 V battery of a pocket calculator is 0.17 mA. In one hour of operation,

Electric Circuits and Electric Current  A flashlight, an electric toaster, and a car’s starting motor all involve electric circuits and electric current.

1 §18.1 Electric Current e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- A metal wire. Assume electrons flow to the right. Current is a measure of the amount of.

PHYS219 Fall semester 2014 Lecture 08: Circuits, Fuses and Kirchhoff’s Laws Dimitrios Giannios Purdue University.

1© Manhattan Press (H.K.) Ltd Potentiometer Comparing resistances Measuring the e.m.f. of a cell Measuring the internal resistance of a cell.

Electric Circuits. Section 1: Electromotive Force & Current.

Electrostatics (Static Electricity) was a single discharge. Current is a steady flow of electric charge.

I Chapter 25 Electric Currents and Resistance. I Problem 5 5. (II) An electric clothes dryer has a heating element with a resistance of 8.6Ω (a) What.

Current Electricity and Elastic Properties

Warm up set 7 Question (a) where a wire is connected to a battery

II. Electric current 1. Definition a) Conventional current Electron

Calculators (without internet connection) are allowed.

Chapter 25 Electric Currents and Resistance

Warm up set 7 Question Answer:

Chapter 9: Current and resistance

Chapter 27 Problems 1,11,12,15,16,22,32,33,36,49,56.

Physics 3 – Nov 20, 2018 P3 Challenge –

Current and Simple Circuits Voltage Resistance Safety

A spherical shell is uniformly charged with a positive charge density . Which of the following statements is (are) true? Select one of (a) – (e). An.

T- Norah Ali Al- moneef king Saud university

Presentation transcript:

Physics 121 Practice Problem Solutions 07 Current and Resistance Contents: 121P07 - 1Q, 4Q, 1P, 7P, 12P, 19P, 25P, 31P, 35P, 38P Circuits and Currents Electric Current i Current Density J Drift Speed Resistance, Resistivity, Conductivity Ohm’s Law Power in Electric Circuits Examples Kirchoff’s Rules applied to Circuits EMF’s - “Pumping” Charges Work, Energy, and EMF Simple Single Loop and Multi-Loop Circuits

PROBLEM 121P07-1Q: The figure shows plots of the current i through a certain cross section of a wire over four different time periods. Rank the periods according to the net charge that passes through the cross section during each, greatest first.

PROBLEM 121P07-4Q: If you stretch a cylindrical wire and it remains cylindrical, does the resistance of the wire (measured end to end along its length) increase, decrease, or remain the same?

PROBLEM 121P07-1P: A current of 5. 0 A exists in a 10 W resistor for 4 PROBLEM 121P07-1P: A current of 5.0 A exists in a 10 W resistor for 4.0 min. How many (a) coulombs and (b) electrons pass through any cross section of the resistor in this time?

PROBLEM 121P07-7P*: A fuse in an electric circuit is a wire that is designed to melt, and thereby open the circuit, if the current exceeds a predetermined value. Suppose that the material to be used in a fuse melts when the current density rises to 440 A/cm2. What diameter of cylindrical wire should be used to make a fuse that will limit the current to 0.50 A?

PROBLEM 121P07-12P: A wire of Nichrome (a nickel–chromium–iron alloy commonly used in heating elements) is 1.0 m long and 1.0 mm2 in cross-sectional area. It carries a current of 4.0 A when a 2.0 V potential difference is applied between its ends. Calculate the conductivity s of Nichrome.

PROBLEM 121P07-19P. : A wire with a resistance of 6 PROBLEM 121P07-19P*: A wire with a resistance of 6.0 W is drawn out through a die so that its new length is three times its original length. Find the resistance of the longer wire, assuming that the resistivity and density of the material are unchanged.

PROBLEM 121P07-25P: A common flashlight bulb is rated at 0. 30 A and 2 PROBLEM 121P07-25P: A common flashlight bulb is rated at 0.30 A and 2.9 V (the values of the current and voltage under operating conditions). If the resistance of the bulb filament at room temperature (20°C) is 1.1 W, what is the temperature of the filament when the bulb is on? The filament is made of tungsten.

PROBLEM 121P07-31P: A certain x-ray tube operates at a current of 7 PROBLEM 121P07-31P: A certain x-ray tube operates at a current of 7.0 mA and a potential difference of 80 kV. What is its power in watts?

PROBLEM 121P07-35P*: An unknown resistor is connected between the terminals of a 3.00 V battery. Energy is dissipated in the resistor at the rate of 0.540 W. The same resistor is then connected between the terminals of a 1.50 V battery. At what rate is energy now dissipated?

PROBLEM 121P07-38P: A heating element is made by maintaining a potential difference of 75.0 V across the length of a Nichrome wire that has a 2.60 x 10-6 m2 cross section. Nichrome has a resistivity of 5.00 x 10-7 W·m. (a) If the element dissipates 5000 W, what is its length? (b) If a potential difference of 100 V is used to obtain the same dissipation rate, what should the length be?