Concept explainers
Explain the difference between current and current density.
Answer to Problem 1FTD
Explanation of Solution
Electric current is the time rate of flow of charges or ions. It is measured using the apparatus called ammeter and the unit of current is ampere. The magnitude of current depends on the potential difference and the resistance.
Write the equation to find the electric current.
Here,
The magnitude of current increases as the number of charges increases.
Write the equation to find the current density.
Here,
The current density can be explained as the amount of current passing through unit area. Current densities are denoted by the symbol
Conclusion:
Electric current is a scalar quantity and current density is a vector quantity. That is electric current has magnitude only but electric current density has both direction and magnitude and also electric current is the flow of charges but current density is the amount of current passing per unit area.
Want to see more full solutions like this?
Chapter 24 Solutions
Essential University Physics: Volume 2 (3rd Edition)
Additional Science Textbook Solutions
Chemistry: A Molecular Approach (4th Edition)
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
Biology: Life on Earth (11th Edition)
Concepts of Genetics (12th Edition)
Human Physiology: An Integrated Approach (8th Edition)
Campbell Biology (11th Edition)
- The velocity of an elevator is given by the graph shown. Assume the positive direction is upward. Velocity (m/s) 3.0 2.5 2.0 1.5 1.0 0.5 0 0 5.0 10 15 20 25 Time (s) (a) Briefly describe the motion of the elevator. Justify your description with reference to the graph. (b) Assume the elevator starts from an initial position of y = 0 at t=0. Deriving any numerical values you need from the graph: i. Write an equation for the position as a function of time for the elevator from t=0 to t = 3.0 seconds. ii. Write an equation for the position as a function of time for the elevator from t = 3.0 seconds to t = 19 seconds. (c) A student of weight mg gets on the elevator and rides the elevator during the time interval shown in the graph. Consider the force of con- tact, F, between the floor and the student. How Justify your answer with reference to the graph does F compare to mg at the following times? and your equations above. i. = 1.0 s ii. = 10.0 sarrow_forwardStudents are asked to use circular motion to measure the coefficient of static friction between two materials. They have a round turntable with a surface made from one of the materials, for which they can vary the speed of rotation. They also have a small block of mass m made from the sec- ond material. A rough sketch of the apparatus is shown in the figure below. Additionally they have equipment normally found in a physics classroom. Axis m (a) Briefly describe a procedure that would allow you to use this apparatus to calculate the coefficient of static friction, u. (b) Based on your procedure, determine how to analyze the data collected to calculate the coefficient of friction. (c) One group of students collects the following data. r (m) fm (rev/s) 0.050 1.30 0.10 0.88 0.15 0.74 0.20 0.61 0.25 0.58 i. Use the empty spaces in the table as needed to calculate quantities that would allow you to use the slope of a line graph to calculate the coefficient of friction, providing labels with…arrow_forwardPART Aarrow_forward
- answer both questionarrow_forwardOnly part A.) of the questionarrow_forwardIn general it is best to conceptualize vectors as arrows in space, and then to make calculations with them using their components. (You must first specify a coordinate system in order to find the components of each arrow.) This problem gives you some practice with the components. Let vectors A = (1,0, -3), B = (-2, 5, 1), and C = (3,1,1). Calculate the following, and express your answers as ordered triplets of values separated by commas.arrow_forward
- In general it is best to conceptualize vectors as arrows in space, and then to make calculations with them using their components. (You must first specify a coordinate system in order to find the components of each arrow.) This problem gives you some practice with the components. Let vectors A = (1,0, −3), B = (-2, 5, 1), and C = (3,1,1). Calculate the following, and express your answers as ordered triplets of values separated by commas.arrow_forwardOnly Part C.) is necessaryarrow_forwardOnly Part B.) is necessaryarrow_forward
- A (3.60 m) 30.0°- 70.0° x B (2.40 m)arrow_forwardIn general it is best to conceptualize vectors as arrows in space, and then to make calculations with them using their components. (You must first specify a coordinate system in order to find the components of each arrow.) This problem gives you some practice with the components. Let vectors A = (1,0, -3), B = (-2, 5, 1), and C = (3,1,1). Calculate the following, and express your answers as ordered triplets of values separated by commas.arrow_forwardfine the magnitude of the vector product express in sq meters what direction is the vector product in -z or +zarrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax College
- Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning