Two cylindrical resistors are made of the same material and have the same resistance.The resistors,R1 and R2,have different radii,r1 and r2,and different lengths,L1 and L2.Which of the following relative values for radii and lengths would result in equal resistances?

A) r1 = r2 and L1 = 2L2 B) 2r1 = r2 and L1 = 2L2 C) r1 = r2 and 4L1 = L2 D) 2r1 = r2 and 4L1 = L2 A) r1 = r2 and L1 = 2L2 B) 2r1 = r2 and L1 = 2L2 C) r1 = r2 and 4L1 = L2 D) 2r1 = r2 and 4L1 = L2

Some superconductors are capable of carrying a very large quantity of current.If the measured current is 1.00 × 105 A,how many electrons are moving through the superconductor per second? (e = 1.60 × 10−19 C)

A) 6.25 × 1023 B) 3.13 × 1022 C) 6.25 × 1021 D) 3.13 × 1020 E) 3.13 × 10-23 A) 6.25 × 1023 B) 3.13 × 1022 C) 6.25 × 1021 D) 3.13 × 1020 E) 3.13 × 10-23

If a metallic wire of cross sectional area 3.0 × 10−6 m2 carries a current of 8.0 A and has a mobile charge density of 4.24 × 1028 carriers/m3,what is the average drift velocity of the mobile charge carriers? (charge value = 1.6 × 10−19 C)

A) 3.1 × 103 m/s B) 1.9 × 103 m/s C) 6.3 × 10−4 m/s D) 3.9 × 10−4 m/s E) 8 × 10−6 m/s A) 3.1 × 103 m/s B) 1.9 × 103 m/s C) 6.3 × 10−4 m/s D) 3.9 × 10−4 m/s E) 8 × 10−6 m/s

Exam 17: Current and Resistance Electric Current

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Resistor A has twice the resistance of resistor B.When individually connected across a given potential difference,which one dissipates the most power;and when connected in series across the same potential difference,which one dissipates the most power?

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You measure a 28-V potential difference across a 7-Ω resistor.What is the current flowing through it?

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A copper cable needs to carry a current of 250 A with a power loss of only 3 W/m.What is the required radius of the copper cable? (The resistivity of copper is 1.7 × 10−⁸ Ω⋅m).

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Two cylindrical resistors are made of the same material and have the same resistance.The resistors,R₁ and R₂,have different radii,r₁ and r₂,and different lengths,L₁ and L₂.Which of the following relative values for radii and lengths would result in equal resistances?

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Question 4

Superconductivity was discovered by:

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Question 5

An electric clothes dryer draws 23 A at 220 V.If the clothes put into the dryer have a mass of 7 kg when wet and 4 kg dry,how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water,L_v = 2.26 × 10⁶ J/kg).

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Question 6

When a superconductor's temperature drops below the critical temperature,its resistance:

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Question 7

The quantity volt is equivalent to which of the following?

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Question 8

If a 550-W heater carries a current of 3 A,what is the voltage across the ends of the heating element?

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Question 9

If the current in a wire is tripled,what effect does this have on the electron drift velocity in the wire?

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Question 10

If a lamp has resistance of 110 Ω when it operates at 100 W,what is the applied voltage?

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Question 11

Number 10 copper wire (radius = 1.7 mm)is commonly used for electrical installations in homes.What is the voltage drop in 41 m of #10 copper wire if it carries a current of 9 A? (The resistivity of copper is 1.7 × 10−⁸ Ω⋅m. )

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Question 12

Some superconductors are capable of carrying a very large quantity of current.If the measured current is 1.00 × 10⁵ A,how many electrons are moving through the superconductor per second? (e = 1.60 × 10−¹⁹ C)

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Question 13

A light bulb has resistance of 210 Ω when operating at 105 V.Find the current in the light bulb.

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Question 14

If a metallic wire of cross sectional area 3.0 × 10−⁶ m² carries a current of 8.0 A and has a mobile charge density of 4.24 × 10²⁸ carriers/m³,what is the average drift velocity of the mobile charge carriers? (charge value = 1.6 × 10−¹⁹ C)

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Question 15

A resistor is made of a material that has a resistivity that is proportional to the current going through it.If the voltage across the resistor is doubled,what happens to the power dissipated by it?

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Question 16

Which is a unit of power?

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Question 17

A resistor is made of a material that has a resistivity that is proportional to the current going through it.If the voltage across the resistor is doubled,what happens to the current through it?

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Question 18

If a 500-W heater carries a current of 4.00 A,what is the resistance of the heating element?

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Question 19

The current in an electron beam in a cathode-ray tube is measured to be 50 µA.How many electrons hit the screen in 4.0 s? (e = 1.6 × 10−¹⁹ C)

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Question 20

Showing 1 - 20 of 83

Exam 17: Current and Resistance Electric Current

Resistor A has twice the resistance of resistor B.When individually connected across a given potential difference,which one dissipates the most power;and when connected in series across the same potential difference,which one dissipates the most power?

You measure a 28-V potential difference across a 7-Ω resistor.What is the current flowing through it?

A copper cable needs to carry a current of 250 A with a power loss of only 3 W/m.What is the required radius of the copper cable? (The resistivity of copper is 1.7 × 10−8 Ω⋅m).

Two cylindrical resistors are made of the same material and have the same resistance.The resistors,R1 and R2,have different radii,r1 and r2,and different lengths,L1 and L2.Which of the following relative values for radii and lengths would result in equal resistances?

Superconductivity was discovered by:

An electric clothes dryer draws 23 A at 220 V.If the clothes put into the dryer have a mass of 7 kg when wet and 4 kg dry,how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water,Lv = 2.26 × 106 J/kg).

When a superconductor's temperature drops below the critical temperature,its resistance:

The quantity volt is equivalent to which of the following?

If a 550-W heater carries a current of 3 A,what is the voltage across the ends of the heating element?

If the current in a wire is tripled,what effect does this have on the electron drift velocity in the wire?

If a lamp has resistance of 110 Ω when it operates at 100 W,what is the applied voltage?

Number 10 copper wire (radius = 1.7 mm)is commonly used for electrical installations in homes.What is the voltage drop in 41 m of #10 copper wire if it carries a current of 9 A? (The resistivity of copper is 1.7 × 10−8 Ω⋅m. )

Some superconductors are capable of carrying a very large quantity of current.If the measured current is 1.00 × 105 A,how many electrons are moving through the superconductor per second? (e = 1.60 × 10−19 C)

A light bulb has resistance of 210 Ω when operating at 105 V.Find the current in the light bulb.

If a metallic wire of cross sectional area 3.0 × 10−6 m2 carries a current of 8.0 A and has a mobile charge density of 4.24 × 1028 carriers/m3,what is the average drift velocity of the mobile charge carriers? (charge value = 1.6 × 10−19 C)

A resistor is made of a material that has a resistivity that is proportional to the current going through it.If the voltage across the resistor is doubled,what happens to the power dissipated by it?

Which is a unit of power?

A resistor is made of a material that has a resistivity that is proportional to the current going through it.If the voltage across the resistor is doubled,what happens to the current through it?

If a 500-W heater carries a current of 4.00 A,what is the resistance of the heating element?

The current in an electron beam in a cathode-ray tube is measured to be 50 µA.How many electrons hit the screen in 4.0 s? (e = 1.6 × 10−19 C)

Introduction

Introduction: Part A

Motion in One Dimension

Motion in One Dimension: Part A

Vectors and Two-Dimensional Motion

Vectors and Two-Dimensional Motion: Part A

The Laws of Motion

The Laws of Motion: Part A

Energy

Energy: Part A

Momentum and Collisions

Momentum and Collisions: Part A

Rotational Motion and the Law of Gravity

Rotational Motion and the Law of Gravity: Part A

Rotational Equilibrium and Rotational Dynamics

Rotational Equilibrium and Rotational Dynamics: Part A

Solids and Fluids

Solids and Fluids: Part A

Thermal Physics

Thermal Physics: Part A

Energy in Thermal Processes Heat and Internal Energy

Energy in Thermal Processes Heat and Internal Energy: Part A

The Laws of Thermodynamics Work in Thermodynamic Processes

The Laws of Thermodynamics Work in Thermodynamic Processes: Part A

Vibrations and Waves

Vibrations and Waves: Part A

Sound

Sound: Part A

Electric Forces and Electric Fields

Electric Forces and Electric Fields: Part A

Electrical Energy and Capacitance

Electrical Energy and Capacitance: Part A

Current and Resistance Electric Current: Part A

Direct-Current Circuits Sources of EMF

Direct-Current Circuits Sources of EMF: Part A

Magnetism Magnets

Magnetism Magnets: Part A

Induced Voltages and Inductance

Induced Voltages and Inductance: Part A

Alternating-Current Circuits and Electromagnetic Waves

Alternating-Current Circuits and Electromagnetic Waves: Part A

Reflection and Refraction of Light

Reflection and Refraction of Light: Part A

Mirrors and Lenses

Mirrors and Lenses: Part A

Wave Optics

Wave Optics: Part A

Optical Instruments

Optical Instruments: Part A

Relativity

Relativity: Part A

Quantum Physics Blackbody Radiation and Plancks Hypothesis

Quantum Physics Blackbody Radiation and Plancks Hypothesis: Part A

Atomic Physics

Atomic Physics: Part A

Nuclear Physics

Nuclear Physics: Part A

Nuclear Energy and Elementary Particles

Nuclear Energy and Elementary Particles: Part A

A copper cable needs to carry a current of 250 A with a power loss of only 3 W/m.What is the required radius of the copper cable? (The resistivity of copper is 1.7 × 10−⁸ Ω⋅m).

Two cylindrical resistors are made of the same material and have the same resistance.The resistors,R₁ and R₂,have different radii,r₁ and r₂,and different lengths,L₁ and L₂.Which of the following relative values for radii and lengths would result in equal resistances?

An electric clothes dryer draws 23 A at 220 V.If the clothes put into the dryer have a mass of 7 kg when wet and 4 kg dry,how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water,L_v = 2.26 × 10⁶ J/kg).

Number 10 copper wire (radius = 1.7 mm)is commonly used for electrical installations in homes.What is the voltage drop in 41 m of #10 copper wire if it carries a current of 9 A? (The resistivity of copper is 1.7 × 10−⁸ Ω⋅m. )

Some superconductors are capable of carrying a very large quantity of current.If the measured current is 1.00 × 10⁵ A,how many electrons are moving through the superconductor per second? (e = 1.60 × 10−¹⁹ C)

If a metallic wire of cross sectional area 3.0 × 10−⁶ m² carries a current of 8.0 A and has a mobile charge density of 4.24 × 10²⁸ carriers/m³,what is the average drift velocity of the mobile charge carriers? (charge value = 1.6 × 10−¹⁹ C)

The current in an electron beam in a cathode-ray tube is measured to be 50 µA.How many electrons hit the screen in 4.0 s? (e = 1.6 × 10−¹⁹ C)