Question 1

Two copper wires have the same volume, but wire 2 is 10% longer than wire 1. The ratio of the resistances of the two wires R₂/R₁ is

Accepted Answer

A

Question 2

You want to use a metal bar as a resistor. Its dimensions are 2 by 4 by 10 units. To get the largest resistance from this bar, you should attach leads to the two opposite sides that have the dimensions of

Accepted Answer

A

Question 3

For copper, ρ = 8.93 g/cm³ and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.435 mm carrying a current of 5 A?

Accepted Answer

D

Question 4

Two copper wires have the same volume, but wire 2 is 20% longer than wire 1. The ratio of the resistances of the two wires R₂/R₁ is

Accepted Answer

The answer of Two copper wires have the same volume,...

Question 5

If 4.7 × 10¹⁶ electrons pass a particular point in a wire every second, what is the current in the wire?

Accepted Answer

To find the current, we need to use the formula: I = Q/t where I is the current in amperes, Q is the charge passing through the point in coulombs, and t is the time in seconds. We are given the number of electrons passing through the point in one second, which is: 4.7 × 10¹⁶ electrons/second To find the charge passing through the point in one second, we need to convert the number of electrons to coulombs. One electron has a charge of 1.6 × 10^-19 coulombs, so: (4.7 × 10¹⁶ electrons/second) × (1.6 × 10^-19 coulombs/electron) = 7.52 × 10^-12 coulombs/second Now we can plug this into the formula for current: I = Q/t = 7.52 × 10^-12 coulombs/second ÷ 1 second = 7.52 × 10^-12 amperes This is equivalent to 7.5 × 10^-3 mA, or 7.5 mA. Therefore, the answer is D.

Question 6

In a certain particle accelerator, a current of 800 μA is carried by a 6.00-MeV proton beam that has a radius of 1.50 mm. The mass of a proton is 1.67 × 10^-27 kg. How many protons per unit volume are in this beam?

Accepted Answer

The answer of In a certain particle accelerator, a current...

Question 7

For copper, ρ = 8.93 g/cm³ and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.625 mm carrying a current of 3 A?

Accepted Answer

The drift velocity $ v_d $ can be calculated using the formula $ v_d = \frac{I}{nAe} $, where $ I $ is the current, $ n $ is the number density of electrons, $ A $ is the cross-sectional area, and $ e $ is the charge of an electron. First, calculate $ n $ using $ n = \frac{\rho \cdot N_A}{M} $, where $ \rho $ is the density, $ N_A $ is Avogadro's number, and $ M $ is the molar mass. Then, calculate $ A = \pi r^2 $ with $ r = 0.625 \times 10^{-3} $ m. Substituting these into the drift velocity formula gives the correct answer.

Question 8

A wire of length L = 5.0 m and uniform diameter has an electric field of E = 4.0 V/m throughout the wire. The potential difference across the wire is

Accepted Answer

The potential difference across the wire can be calculated using the formula:

V = E * L

where E is the electric field and L is the length of the wire.

Substituting the given values, we get:

V = 4.0 V/m * 5.0 m

V = 20.0 V

Therefore, the potential difference across the wire is 20.0 V. The correct answer is choice C.

Question 9

In a certain particle accelerator, a current of 300 μA is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 × 10^-27 kg. What is the number of protons per unit volume in this beam?

Accepted Answer

The answer of In a certain particle accelerator, a current...

Question 10

Which of the following statements is false?

Accepted Answer

The electric field is not constant along all parts of the circuit when a steady current is flowing. Instead, it can vary depending on the resistance or other properties of the circuit components.

Question 11

The drift velocity of an electron in a wire varies

Accepted Answer

The drift velocity of an electron in a wire is directly proportional to the current flowing in the conducting wire, according to the relationship v = I / (neA), where v is drift velocity, I is current, n is the number of charge carriers per unit volume, e is the charge carried by an electron, and A is the cross-sectional area of the conducting wire.

Question 12

Which of the following statements is false?

Accepted Answer

In the absence of an electric field, the average velocity of the electrons in a wire is not very large. The correct statement is that the electrons move in random directions with speeds of the order of 10^6 m/s, but the average velocity is zero.

Question 13

A potential difference V = 25 V is applied across a wire of length L = 10.0 m and uniform diameter. The electric field throughout the wire is

Accepted Answer

The electric field (E) in a uniform wire is given by the potential difference (V) divided by the length (L) of the wire. Thus, E = V/L = 25 V / 10.0 m = 2.5 V/m.

Question 14

A potential difference of 120 V produces a current of 8.0 A in the heating element of a toaster. What is the resistance of this heating element while the toaster is carrying this current?

Accepted Answer

The resistance can be calculated using Ohm's Law: R = V/I = 120V / 8.0A = 15 Ω.

Question 15

In a certain particle accelerator, a current of 800 μA is carried by a 6.00-MeV proton beam that has a radius of 1.50 mm. The mass of a proton is 1.67 × 10^-27 kg. If the beam hits a target, how many protons hit the target in 5 s?

Accepted Answer

The number of protons hitting the target is calculated by dividing the total charge by the charge of a single proton. Total charge = current × time = 800 μA × 5 s = 4 × 10^-3 C. The charge of a proton is approximately 1.6 × 10^-19 C. Therefore, the number of protons = (4 × 10^-3 C) / (1.6 × 10^-19 C/proton) = 2.5 × 10^16 protons.

Question 16

A 10-gauge copper wire diameter = 2.588 mm, ρ = 1.7 × 10^-8 Ω · m) has a total resistance of 0.32 Ω. How long is the wire?

Accepted Answer

The resistance of a wire is given by:$$R = ho \frac{L}{A}$$where:* R is the resistance in ohms (Ω)* ρ is the resistivity of the wire in ohm-meters (Ω·m)* L is the length of the wire in meters (m)* A is the cross-sectional area of the wire in square meters (m²)We are given the following information:* R = 0.32 Ω* ρ = 1.7 × 10^-8 Ω·m* d = 2.588 mm = 2.588 × 10^-3 mThe cross-sectional area of the wire is:$$A = \frac{\pi d^2}{4} = \frac{\pi (2.588 	imes 10^{-3} 	ext{ m})^2}{4} = 5.262 	imes 10^{-6} 	ext{ m}^2$$Substituting these values into the equation for resistance, we get:$$0.32 \Omega = 1.7 	imes 10^{-8} \Omega \cdot 	ext{m} \cdot \frac{L}{5.262 	imes 10^{-6} 	ext{ m}^2}$$Solving for L, we get:$$L = \frac{0.32 \Omega \cdot 5.262 	imes 10^{-6} 	ext{ m}^2}{1.7 	imes 10^{-8} \Omega \cdot 	ext{m}} = 99 	ext{ m}$$Therefore, the length of the wire is 99 m.

Question 17

In a certain particle accelerator, a current of 300 μA is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 × 10^-27 kg. If the beam hits a target, how many protons hit the target in 3 s?

Accepted Answer

The answer of In a certain particle accelerator, a current...

Question 18

The resistivity of any given metal

Accepted Answer

The resistivity of any given metal depends on its temperature, varies linearly with temperature, is the proportionality constant between the resistance, R, and the ratio of the length, L, to the cross-sectional area, A, of a wire made of the metal, and has units of ohm-meter. Therefore, all of the given options are correct.

Question 19

You want to use a metal bar as a resistor. Its dimensions are 2 by 4 by 10 units. To get the smallest resistance from this bar, you should attach leads to the two opposite sides that have the dimensions of

Accepted Answer

The resistance of a metal bar is directly proportional to its length and inversely proportional to its cross-sectional area. Therefore, to get the smallest resistance, we want to maximize the cross-sectional area and minimize the length between the two leads. The two sides with dimensions of 4 by 10 units have a larger cross-sectional area than the sides with dimensions of 2 by 10 or 2 by 4 units. Therefore, attaching the leads to the 4 by 10 sides will result in the smallest resistance.

Question 20

The seemingly instantaneous propagation of electric current in a wire when a switch is closed can be understood in terms of

Accepted Answer

The answer of The seemingly instantaneous propagation of electric current...

Quiz 18: Electric Charges in Motion

Two copper wires have the same volume, but wire 2 is 10% longer than wire 1. The ratio of the resistances of the two wires R2/R1 is

You want to use a metal bar as a resistor. Its dimensions are 2 by 4 by 10 units. To get the largest resistance from this bar, you should attach leads to the two opposite sides that have the dimensions of

For copper, ρ = 8.93 g/cm3 and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.435 mm carrying a current of 5 A?

Two copper wires have the same volume, but wire 2 is 20% longer than wire 1. The ratio of the resistances of the two wires R2/R1 is

If 4.7 × 1016 electrons pass a particular point in a wire every second, what is the current in the wire?

In a certain particle accelerator, a current of 800 μA is carried by a 6.00-MeV proton beam that has a radius of 1.50 mm. The mass of a proton is 1.67 × 10-27 kg. How many protons per unit volume are in this beam?

For copper, ρ = 8.93 g/cm3 and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.625 mm carrying a current of 3 A?

A wire of length L = 5.0 m and uniform diameter has an electric field of E = 4.0 V/m throughout the wire. The potential difference across the wire is

In a certain particle accelerator, a current of 300 μA is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 × 10-27 kg. What is the number of protons per unit volume in this beam?

Which of the following statements is false?

The drift velocity of an electron in a wire varies

Which of the following statements is false?

A potential difference V = 25 V is applied across a wire of length L = 10.0 m and uniform diameter. The electric field throughout the wire is

A potential difference of 120 V produces a current of 8.0 A in the heating element of a toaster. What is the resistance of this heating element while the toaster is carrying this current?

In a certain particle accelerator, a current of 800 μA is carried by a 6.00-MeV proton beam that has a radius of 1.50 mm. The mass of a proton is 1.67 × 10-27 kg. If the beam hits a target, how many protons hit the target in 5 s?

A 10-gauge copper wire diameter = 2.588 mm, ρ = 1.7 × 10-8 Ω · m) has a total resistance of 0.32 Ω. How long is the wire?

In a certain particle accelerator, a current of 300 μA is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 × 10-27 kg. If the beam hits a target, how many protons hit the target in 3 s?

The resistivity of any given metal

You want to use a metal bar as a resistor. Its dimensions are 2 by 4 by 10 units. To get the smallest resistance from this bar, you should attach leads to the two opposite sides that have the dimensions of

The seemingly instantaneous propagation of electric current in a wire when a switch is closed can be understood in terms of

Two copper wires have the same volume, but wire 2 is 10% longer than wire 1. The ratio of the resistances of the two wires R₂/R₁ is

For copper, ρ = 8.93 g/cm³ and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.435 mm carrying a current of 5 A?

Two copper wires have the same volume, but wire 2 is 20% longer than wire 1. The ratio of the resistances of the two wires R₂/R₁ is

If 4.7 × 10¹⁶ electrons pass a particular point in a wire every second, what is the current in the wire?

In a certain particle accelerator, a current of 800 μA is carried by a 6.00-MeV proton beam that has a radius of 1.50 mm. The mass of a proton is 1.67 × 10^-27 kg. How many protons per unit volume are in this beam?

For copper, ρ = 8.93 g/cm³ and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.625 mm carrying a current of 3 A?

In a certain particle accelerator, a current of 300 μA is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 × 10^-27 kg. What is the number of protons per unit volume in this beam?

In a certain particle accelerator, a current of 800 μA is carried by a 6.00-MeV proton beam that has a radius of 1.50 mm. The mass of a proton is 1.67 × 10^-27 kg. If the beam hits a target, how many protons hit the target in 5 s?

A 10-gauge copper wire diameter = 2.588 mm, ρ = 1.7 × 10^-8 Ω · m) has a total resistance of 0.32 Ω. How long is the wire?

In a certain particle accelerator, a current of 300 μA is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 × 10^-27 kg. If the beam hits a target, how many protons hit the target in 3 s?