A wire of radius R carries a current I.The current density is given by the function J = J0 (1 - r/R)where r is measured from the center of the wire and J0 is a constant.What is the value of J0 if I = 1A,R = 1.5 mm (in A/m2)?

A) 3.18 * 10-1 B) 4.76 * 103 C) 1.06 * 105 D) 4.24 * 105 E) 2.12 * 105 A) 3.18 * 10-1 B) 4.76 * 103 C) 1.06 * 105 D) 4.24 * 105 E) 2.12 * 105

Exam 25: Current and Resistance

The resistivity of gold at room temperature is 2.35 * 10^-8 $\varOmega$ m.The temperature coefficient $\alpha$ = 3.98 10^-3/K.What will be the resistivity of a piece of gold whose temperature is 150^$\circ$C above room temperature?

(Multiple Choice)

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Question 21

A wire of length L,diameter d,resistance R is made of material with resistivity $\rho$ .If I take the wire and cut it into five equal pieces and then put those pieces in parallel to make one single thick wire L/5 in length,what will be its resistance?

(Multiple Choice)

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Question 22

A ribbon of nichrome (resistivity = 1.00 * 10^-6 $\varOmega$ ·m)with a rectangular cross sectional area of (0.25 mm * 1.00 mm)and 21.9 cm in length is used as a heating element in a toaster.What is the total resistance of this ribbon?

(Multiple Choice)

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Question 23

The current in an 11-gauge wire copper wire is 1.0 A and the wire is 170 m long.What is the potential difference across the wire?

(Multiple Choice)

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Question 24

Two resistors of resistance R are connected in series.The combination is connected in parallel to a resistor of resistance 2R.What is the resistance of this combination of resistors?

(Multiple Choice)

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Question 25

What is the total power dissipated in both resistors?

(Multiple Choice)

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Question 26

Which of the following has the largest current flowing through it?

(Multiple Choice)

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Question 27

A circuit consists of a copper wire of length 10 m and radius 1 mm.The wire is connected to a 10-V battery.An aluminum wire of radius 0.50 mm is connected to the same battery and dissipates the same amount of power.What is the length of the aluminum wire?

(Multiple Choice)

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Question 28

What is the current that flows out of the ideal 9-V battery in the circuit in the figure?

(Multiple Choice)

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Question 29

In the circuit shown,R1 = 9.00 $\varOmega$ ,R2 = 14.0 $\varOmega$ ,R3 = 2.50 $\varOmega$ ,and V = 16.0 V.Find the total power dissipated in the circuit (in W). $In the circuit shown,R1 = 9.00 \varOmega ,R2 = 14.0 \varOmega ,R3 = 2.50 \varOmega ,and V = 16.0 V.Find the total power dissipated in the circuit (in W).$

(Multiple Choice)

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Question 30

If the electric potential across a resistor is increased by a factor of 4,how does this affect the power dissipated?

(Multiple Choice)

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Question 31

A copper wire has a diameter of d_Cu = 0.0400 cm,is 3.00 m long,has a resistivity of 1.72 * 10^-8 $\varOmega$ m and has a carrier density of 8.50 * 10²⁸ electrons/m³.The copper wire is attached to an equal length of aluminum wire with a diameter of d_Al = 0.0200 cm,and a carrier density of 6.02 * 10²⁸ electrons/m³.A current of 0.400 A flows through the copper and aluminum wires.What is the ratio of the current densities J_Cu/J_Al in the two wires?

(Multiple Choice)

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Question 32

At a critical junction in a supercomputer,the current as a function of time is given as i(t)= 3t² -2t,where i is measured in milliamps and t is measured in seconds.How much charge passes through this critical junction during the interval 0 < t < 5.00 s?

(Multiple Choice)

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Question 33

A particular wire has a diameter of 1.7 mm and length of 1.3 m.If its resistance is 15 m $\varOmega$ ,what is the resistivity of the metal from which it is made?

(Multiple Choice)

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Question 34

When two resistors are connected in parallel across a 12-V battery,6.3 A flows.If the smaller resistor is 2.5 $\varOmega$ how much current flows when the two are put in series across the same battery?

(Multiple Choice)

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Question 35

A resistor of unknown resistance and a 52-W resistor are connected across a 120-V emf in such a way that a 12-A current is observed in the emf.What is the value of the unknown resistance?

(Multiple Choice)

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Question 36

What is the current supplied by the battery?

(Multiple Choice)

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Question 37

A potential difference of V = 0.500 V is applied across the length of a rectangular block of silicon (Si)with resistivity 8.70 *10^-4 $\varOmega$ m.The dimensions of the Si block are: width 1.50 mm;thickness 0.400 mm;and length L = 20.0 cm.You may assume that the current density in the Si block is uniform and that currents in Si obey Ohm's law.What is the resistance of this Si block?

(Multiple Choice)

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Question 38

Two resistors of resistance R are connected in parallel.The combination is connected in series to a resistor of resistance 2R.What is the resistance of this combination of resistors?

(Multiple Choice)

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Question 39

A wire of radius R carries a current I.The current density is given by the function J = J₀ (1 - r/R)where r is measured from the center of the wire and J₀ is a constant.What is the value of J₀ if I = 1A,R = 1.5 mm (in A/m²)?

(Multiple Choice)

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Question 40

Showing 21 - 40 of 80

Exam 25: Current and Resistance

The resistivity of gold at room temperature is 2.35 * 10-8 Ω\varOmegaΩ *m.The temperature coefficient α\alphaα = 3.98 * 10-3/K.What will be the resistivity of a piece of gold whose temperature is 150 ∘\circ∘ C above room temperature?

A wire of length L,diameter d,resistance R is made of material with resistivity ρ\rhoρ .If I take the wire and cut it into five equal pieces and then put those pieces in parallel to make one single thick wire L/5 in length,what will be its resistance?

A ribbon of nichrome (resistivity = 1.00 * 10-6 Ω\varOmegaΩ ·m)with a rectangular cross sectional area of (0.25 mm * 1.00 mm)and 21.9 cm in length is used as a heating element in a toaster.What is the total resistance of this ribbon?

The current in an 11-gauge wire copper wire is 1.0 A and the wire is 170 m long.What is the potential difference across the wire?

Two resistors of resistance R are connected in series.The combination is connected in parallel to a resistor of resistance 2R.What is the resistance of this combination of resistors?

What is the total power dissipated in both resistors?

Which of the following has the largest current flowing through it?

A circuit consists of a copper wire of length 10 m and radius 1 mm.The wire is connected to a 10-V battery.An aluminum wire of radius 0.50 mm is connected to the same battery and dissipates the same amount of power.What is the length of the aluminum wire?

What is the current that flows out of the ideal 9-V battery in the circuit in the figure?

In the circuit shown,R1 = 9.00 Ω\varOmegaΩ ,R2 = 14.0 Ω\varOmegaΩ ,R3 = 2.50 Ω\varOmegaΩ ,and V = 16.0 V.Find the total power dissipated in the circuit (in W).

If the electric potential across a resistor is increased by a factor of 4,how does this affect the power dissipated?

At a critical junction in a supercomputer,the current as a function of time is given as i(t)= 3t2 -2t,where i is measured in milliamps and t is measured in seconds.How much charge passes through this critical junction during the interval 0 < t < 5.00 s?

A particular wire has a diameter of 1.7 mm and length of 1.3 m.If its resistance is 15 m Ω\varOmegaΩ ,what is the resistivity of the metal from which it is made?

When two resistors are connected in parallel across a 12-V battery,6.3 A flows.If the smaller resistor is 2.5 Ω\varOmegaΩ how much current flows when the two are put in series across the same battery?

A resistor of unknown resistance and a 52-W resistor are connected across a 120-V emf in such a way that a 12-A current is observed in the emf.What is the value of the unknown resistance?

What is the current supplied by the battery?

Two resistors of resistance R are connected in parallel.The combination is connected in series to a resistor of resistance 2R.What is the resistance of this combination of resistors?

A wire of radius R carries a current I.The current density is given by the function J = J0 (1 - r/R)where r is measured from the center of the wire and J0 is a constant.What is the value of J0 if I = 1A,R = 1.5 mm (in A/m2)?

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The resistivity of gold at room temperature is 2.35 * 10^-8 $\varOmega$ m.The temperature coefficient $\alpha$ = 3.98 10^-3/K.What will be the resistivity of a piece of gold whose temperature is 150^$\circ$C above room temperature?

A wire of length L,diameter d,resistance R is made of material with resistivity $\rho$ .If I take the wire and cut it into five equal pieces and then put those pieces in parallel to make one single thick wire L/5 in length,what will be its resistance?

A ribbon of nichrome (resistivity = 1.00 * 10^-6 $\varOmega$ ·m)with a rectangular cross sectional area of (0.25 mm * 1.00 mm)and 21.9 cm in length is used as a heating element in a toaster.What is the total resistance of this ribbon?

At a critical junction in a supercomputer,the current as a function of time is given as i(t)= 3t² -2t,where i is measured in milliamps and t is measured in seconds.How much charge passes through this critical junction during the interval 0 < t < 5.00 s?

A particular wire has a diameter of 1.7 mm and length of 1.3 m.If its resistance is 15 m $\varOmega$ ,what is the resistivity of the metal from which it is made?

When two resistors are connected in parallel across a 12-V battery,6.3 A flows.If the smaller resistor is 2.5 $\varOmega$ how much current flows when the two are put in series across the same battery?

A wire of radius R carries a current I.The current density is given by the function J = J₀ (1 - r/R)where r is measured from the center of the wire and J₀ is a constant.What is the value of J₀ if I = 1A,R = 1.5 mm (in A/m²)?