Exam 22: Current and Resistance

A wire of resistivity ρ must be replaced in a circuit by a wire of the same material but four times as long. If, however, the total resistance is to remain as before, the diameter of the new wire must

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Question 101

If we double the resistance in a circuit but keep the current in it constant, the power dissipated by that circuit will

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Question 102

The graph shown in the figure shows the results of measurements of the dc current through a circuit device for various potential differences across it. Assume that all the numbers shown are accurate to two significant figures. What is the resistance of this device?

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Question 103

The figure shows a graph of the power dissipated in a resistor as a function of the resistance. What quantity does the slope of this graph represent?

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Question 104

Which one of the following quantities is equivalent to 1 Ω?

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Question 105

The heating element of a toaster is a 5.4-m length of nichrome wire of diameter 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10^-6 Ω ∙ m. The toaster is designed to operate at a voltage of 120 V. How much power does it draw in normal operation?

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Question 106

You are given a copper bar of dimensions 3 cm × 5 cm × 8 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the smallest possible resistance, you should attach the leads to the opposite faces that measure

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Question 107

A battery supplies 6.0 mA to a 12-? resistor for 1.5 h. How much electric energy does this resistor dissipate in this time?

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Question 108

The power rating of a 400-Ω resistor is 0.25 W. What is the maximum voltage you can safely connect across its ends?

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Question 109

Copper wire #1 has a length L and a radius b. Copper wire #2 has a length 2L and a radius 2b. Which statement about the resistance across the ends of the wires is true?

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Question 110

If a charge of 11.4 C passes through a computer in 1.75 min, what is the average current through the computer?

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Question 111

A 100-W resistance heater is connected to a 110-V dc source. What current flows through the heater?

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Question 112

A metal bar is 20 cm long and has a rectangular cross-section measuring 1.0 cm × 2.0 cm. What is the voltage drop along its length when it carries a 4000-A current? The resistivity of the metal is 1.68 × 10^-8 Ω ∙ m.

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Question 113

The length of a certain wire is doubled and at the same time its radius is reduced by a factor of 2. What is the new resistance of this wire?

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Question 114

If a quantity you calculated has units of A ∙ s, what is that quantity?

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Question 115

A battery is rated such that it provides $1.0 \mathrm {~mW}$ of power at $9.0 \mathrm {~V}$ when fully charged. How much current can it deliver?

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Question 116

The resistivity of gold is $2.44 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$ at a temperature of 20°C. A gold wire, 1.8 mm in diameter and 14 cm long, carries a current of 480 mA. What power is dissipated in this wire at 20°C?

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Question 117

What is the voltage drop across a 5.0-Ω resistor if the current through it is 5.0 A?

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Question 118

A light bulb operating at a dc voltage of 120 V has a resistance of 200 Ω. How much power is dissipated in this bulb?

(Multiple Choice)

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Question 119

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

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Question 120

Showing 101 - 120 of 124

Exam 22: Current and Resistance

A wire of resistivity ρ must be replaced in a circuit by a wire of the same material but four times as long. If, however, the total resistance is to remain as before, the diameter of the new wire must

If we double the resistance in a circuit but keep the current in it constant, the power dissipated by that circuit will

The graph shown in the figure shows the results of measurements of the dc current through a circuit device for various potential differences across it. Assume that all the numbers shown are accurate to two significant figures. What is the resistance of this device?

The figure shows a graph of the power dissipated in a resistor as a function of the resistance. What quantity does the slope of this graph represent?

Which one of the following quantities is equivalent to 1 Ω?

The heating element of a toaster is a 5.4-m length of nichrome wire of diameter 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 Ω ∙ m. The toaster is designed to operate at a voltage of 120 V. How much power does it draw in normal operation?

You are given a copper bar of dimensions 3 cm × 5 cm × 8 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the smallest possible resistance, you should attach the leads to the opposite faces that measure

A battery supplies 6.0 mA to a 12-? resistor for 1.5 h. How much electric energy does this resistor dissipate in this time?

The power rating of a 400-Ω resistor is 0.25 W. What is the maximum voltage you can safely connect across its ends?

Copper wire #1 has a length L and a radius b. Copper wire #2 has a length 2L and a radius 2b. Which statement about the resistance across the ends of the wires is true?

If a charge of 11.4 C passes through a computer in 1.75 min, what is the average current through the computer?

A 100-W resistance heater is connected to a 110-V dc source. What current flows through the heater?

A metal bar is 20 cm long and has a rectangular cross-section measuring 1.0 cm × 2.0 cm. What is the voltage drop along its length when it carries a 4000-A current? The resistivity of the metal is 1.68 × 10-8 Ω ∙ m.

The length of a certain wire is doubled and at the same time its radius is reduced by a factor of 2. What is the new resistance of this wire?

If a quantity you calculated has units of A ∙ s, what is that quantity?

A battery is rated such that it provides 1.0 mW1.0 \mathrm {~mW}1.0 mW of power at 9.0 V9.0 \mathrm {~V}9.0 V when fully charged. How much current can it deliver?

The resistivity of gold is 2.44×10−8Ω⋅m2.44 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }2.44×10−8Ω⋅m at a temperature of 20°C. A gold wire, 1.8 mm in diameter and 14 cm long, carries a current of 480 mA. What power is dissipated in this wire at 20°C?

What is the voltage drop across a 5.0-Ω resistor if the current through it is 5.0 A?

A light bulb operating at a dc voltage of 120 V has a resistance of 200 Ω. How much power is dissipated in this bulb?

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

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The heating element of a toaster is a 5.4-m length of nichrome wire of diameter 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10^-6 Ω ∙ m. The toaster is designed to operate at a voltage of 120 V. How much power does it draw in normal operation?

A metal bar is 20 cm long and has a rectangular cross-section measuring 1.0 cm × 2.0 cm. What is the voltage drop along its length when it carries a 4000-A current? The resistivity of the metal is 1.68 × 10^-8 Ω ∙ m.

A battery is rated such that it provides $1.0 \mathrm {~mW}$ of power at $9.0 \mathrm {~V}$ when fully charged. How much current can it deliver?

The resistivity of gold is $2.44 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$ at a temperature of 20°C. A gold wire, 1.8 mm in diameter and 14 cm long, carries a current of 480 mA. What power is dissipated in this wire at 20°C?