Exam 27: Current and Resistance

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Nichrome wire,often used for heating elements,has resistivity of 1.0 × 10^-6 Ω ∙ m at room temperature.What length of No.30 wire (of diameter 0.250 mm)is needed to wind a resistor that has 50 ohms at room temperature?

(Multiple Choice)

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Question 21

When a potential difference of 10 V is placed across a certain solid cylindrical resistor,the current through it is 2 A.If the diameter of this resistor is now tripled,the current will be

(Multiple Choice)

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Question 22

A silver wire with resistivity carries a current density of What is the magnitude of the electric field inside the wire?

(Multiple Choice)

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Question 23

A cylindrical wire of radius 2.0 mm carries a current of 2.5 A.The potential difference between points on the wire that are 46 m apart is 3.7 V. (a)What is the electric field in the wire? (b)What is the resistivity of the material of which the wire is made?

(Essay)

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Question 24

The figure shows a 2.0-cm diameter roller that turns at 90 rpm.A 4.0-cm wide plastic film is being wrapped onto the roller,and this plastic carries an excess electric charge having a uniform surface charge density of 5.0 nC/cm².What is the current of the moving film?

(Multiple Choice)

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Question 25

The resistivity of gold is at room temperature.A gold wire that is 0.9 mm in diameter and 14 cm long carries a current of 940 mA.What is the electric field in the wire?

(Multiple Choice)

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Question 26

The current in a wire varies with time according to the equation I(t)= 6.00 A + (4.80 A/s)t,where t is in seconds.How many coulombs of charge pass a cross section of the wire in the time period between t = 0.00 s and

(Short Answer)

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Question 27

As current flows through a uniform wire,the wire gets hotter because the electrons stop moving and therefore transform their lost kinetic energy into thermal energy in the wire.

(True/False)

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Question 28

When electric current is flowing in a metal,the electrons are moving

(Multiple Choice)

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Question 29

The diameter of a 12-gauge copper wire is 0.081 in.The maximum safe current it can carry (in order to prevent fire danger in building construction)is 20 A.At this current,what is the drift velocity of the electrons? The number of electron carriers in 1.0 cm³ of copper is 8.5 × 10²² and e = 1.60 × 10^-19 C.

(Multiple Choice)

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Question 30

What must be the diameter of a cylindrical 120-m long metal wire if its resistance is to be 6.0 Ω? The resistivity of this metal is 1.68 × 10^-8 Ω ∙ m.

(Multiple Choice)

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Question 31

Calculate the current through a 10.0-m long 22 gauge (having radius 0.321 mm)nichrome wire if it is connected to a 12.0-V battery.The resistivity of nichrome is 100 × 10^-8 Ω ∙ m.

(Multiple Choice)

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Question 32

Showing 21 - 32 of 32

Exam 27: Current and Resistance

Nichrome wire,often used for heating elements,has resistivity of 1.0 × 10-6 Ω ∙ m at room temperature.What length of No.30 wire (of diameter 0.250 mm)is needed to wind a resistor that has 50 ohms at room temperature?

When a potential difference of 10 V is placed across a certain solid cylindrical resistor,the current through it is 2 A.If the diameter of this resistor is now tripled,the current will be

A silver wire with resistivity carries a current density of What is the magnitude of the electric field inside the wire?

A cylindrical wire of radius 2.0 mm carries a current of 2.5 A.The potential difference between points on the wire that are 46 m apart is 3.7 V. (a)What is the electric field in the wire? (b)What is the resistivity of the material of which the wire is made?

The figure shows a 2.0-cm diameter roller that turns at 90 rpm.A 4.0-cm wide plastic film is being wrapped onto the roller,and this plastic carries an excess electric charge having a uniform surface charge density of 5.0 nC/cm2.What is the current of the moving film?

The resistivity of gold is at room temperature.A gold wire that is 0.9 mm in diameter and 14 cm long carries a current of 940 mA.What is the electric field in the wire?

The current in a wire varies with time according to the equation I(t)= 6.00 A + (4.80 A/s)t,where t is in seconds.How many coulombs of charge pass a cross section of the wire in the time period between t = 0.00 s and

As current flows through a uniform wire,the wire gets hotter because the electrons stop moving and therefore transform their lost kinetic energy into thermal energy in the wire.

When electric current is flowing in a metal,the electrons are moving

What must be the diameter of a cylindrical 120-m long metal wire if its resistance is to be 6.0 Ω? The resistivity of this metal is 1.68 × 10-8 Ω ∙ m.

Calculate the current through a 10.0-m long 22 gauge (having radius 0.321 mm)nichrome wire if it is connected to a 12.0-V battery.The resistivity of nichrome is 100 × 10-8 Ω ∙ m.

Concepts of Motion

Kinematics in One Dimension

Vectors and Coordinate Systems

Kinematics in Two Dimensions

Force and Motion

Dynamics I: Motion Along a Line

Newtons Third Law

Dynamics II: Motion in a Plane

Work and Kinetic Energy

Interactions and Potential Energy

Impulse and Momentum

Rotation of a Rigid Body

Newtons Theory of Gravity

Fluids and Elasticity

Oscillations

Traveling Waves

Superposition

A Macroscopic Description of Matter

Work, heat, and the First Law of Thermodynamics

The Micromacro Connection

Heat Engines and Refrigerators

Electric Charges and Forces

The Electric Field

Gausss Law

The Electric Potential

Potential and Field

Fundamentals of Circuits

The Magnetic Field

Electromagnetic Induction

Electromagnetic Fields and Waves

Ac Circuits

Wave Optics

Ray Optics

Optical Instruments

Relativity

The Foundations of Modern Physics

Quantization

Wave Functions and Uncertainty

One-Dimensional Quantum Mechanics

Atomic Physics

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Nichrome wire,often used for heating elements,has resistivity of 1.0 × 10^-6 Ω ∙ m at room temperature.What length of No.30 wire (of diameter 0.250 mm)is needed to wind a resistor that has 50 ohms at room temperature?

The figure shows a 2.0-cm diameter roller that turns at 90 rpm.A 4.0-cm wide plastic film is being wrapped onto the roller,and this plastic carries an excess electric charge having a uniform surface charge density of 5.0 nC/cm².What is the current of the moving film?

What must be the diameter of a cylindrical 120-m long metal wire if its resistance is to be 6.0 Ω? The resistivity of this metal is 1.68 × 10^-8 Ω ∙ m.

Calculate the current through a 10.0-m long 22 gauge (having radius 0.321 mm)nichrome wire if it is connected to a 12.0-V battery.The resistivity of nichrome is 100 × 10^-8 Ω ∙ m.