Physics Chapter on Charge and Thermodynamics

Questions and Answers

Which of the following is the most accurate statement concerning charge?

Charge has no units.

Charge can be created and destroyed.

Charge is an independent dimension.

Charge is a derived dimension (current time), with SI units of Coulombs. (correct)

Which of the following is the most accurate statement concerning electrical force?

Electrical force obeys the inverse square law. (correct)

Electrical force has no relation to distance.

Electrical force is a constant force.

Electrical force can only act in one direction.

Which of the following is the most accurate statement concerning the first law of thermodynamics?

Energy can be destroyed.

Energy is always constant.

Energy can be created.

Energy cannot be created or destroyed. (correct)

What is the most accurate statement concerning the second law of thermodynamics?

No cyclic thermodynamic process can convert heat completely into mechanical work. Signup and view all the answers

What is the most accurate statement concerning the relationship between entropy and the second law of thermodynamics?

More than one of these statements (a, b or c) are accurate. Signup and view all the answers

If you run a Carnot heat engine in reverse, which of the following statements must be true?

More than one of the above statements are true. Signup and view all the answers

What is the most accurate statement concerning Gauss's law?

Gauss's law provides a quantitative relationship between electric charge and the electric field associated with the electric charges enclosed on the surface of a three-dimensional object like a sphere. Signup and view all the answers

If the electric field is 'E' at a distance 'd' from a point charge, its magnitude will be 2E at a distance _____

d/√2. Signup and view all the answers

Two protons close to each other are released from rest and are completely free to move. After being released, which statement(s) is/are accurate?

More than one of the statements (a, b, c or d) are accurate. Signup and view all the answers

Point P is equidistant from two point charges + and - Q of equal magnitude. If a negative point charge is placed at P without moving the original charges, the net electrical force the charges + and - Q will exert on it is _____

Directly upward. Signup and view all the answers

An electron is released from rest in an electric field. The electron accelerates vertically upward, traveling 4.50 m in the first 3.00 microseconds (μs) after it is released. What are the magnitude and direction of the electric field?

5.7 N/C downward. Signup and view all the answers

A charge Q and a charge 3Q are released in a uniform electric field. If the force this field exerts on 3Q is F, what force does it exert on Q?

F/3. Signup and view all the answers

An electric field of magnitude E is measured at a distance R from a point charge Q. If the charge is doubled to 2Q, and the electric field is now measured at a distance of 2R from the charge, what is the value of the new electric field?

E/2. Signup and view all the answers

A point charge Q at the center of a sphere of radius R produces an electric flux of ΦE coming out of the sphere. If the charge remains the same but the radius of the sphere is doubled, what is the electric flux coming out of the sphere?

ΦE. Signup and view all the answers

You put 250 g of water into the freezer and make ice cubes. Which of the following is true about this process?

More than one of the statements above are true. Signup and view all the answers

You want to increase the efficiency of a Carnot engine by changing the temperature of either its hot or cold reservoir by the same number of degrees ΔT. Which of the following choices will produce the greater increase in its thermodynamic efficiency?

Decrease the temperature of the cold reservoir by ΔT. Signup and view all the answers

The thermal efficiency equation e = W/Qh is valid for which of the following heat engines?

All types of heat engines. Signup and view all the answers

At what approximate distance from a particle with a charge of 5.00 nC does the electric field of that charge have a magnitude of 4.00 N/C?

3.4 m. Signup and view all the answers

A 9.6-μC point charge is at the center of a cube with sides of length 0.500 m. What is the electric flux through one face of the cube?

1.80E5 N-m²/C. Signup and view all the answers

A -5.00-nC point charge is on the x-axis at x = 1.20 m. A second point charge Q is on the x-axis at -0.600 m. If the resultant electric field at the origin is 45.0 N/C in the +x direction, what is the sign and magnitude of charge Q?

<ul> <li>5.5E-10 C.</li> </ul> Signup and view all the answers

Study Notes

Charge and Electrical Concepts

Charge is a derived dimension measured in Coulombs, expressed as current multiplied by time.
Electrical force adheres to the inverse square law, indicating forces diminish with the square of the distance.

Thermodynamics Principles

The first law of thermodynamics has multiple accurate statements about energy conservation.
The second law states that no cyclic thermodynamic process can convert heat entirely into mechanical work, establishing limits on efficiency.

Entropy and Thermodynamic Systems

Multiple accurate statements exist regarding the relationship between entropy and the second law of thermodynamics.
Running a Carnot heat engine in reverse has more than one true implication related to energy transfer.

Gauss's Law

Gauss's law quantitatively relates electric charge to the electric field produced by charges enclosed within a surface, such as a sphere.

Electric Field Calculations

If the electric field "E" is present at a distance "d" from a charge, it will be 2E at a distance of d/√2.
In a scenario with two released protons, multiple statements may accurately describe their behavior post-release.

Electric Forces and Point Charges

Point P, equidistant from charges +Q and -Q, will experience an upward net electrical force when a negative charge is introduced.
An electron, released from rest in an electric field, accelerates upward, traveling 4.50 m in a brief timeframe, suggesting a downward electric field of 5.7 N/C.

Charge Interactions

If 3Q experiences force F in a uniform electric field, then charge Q experiences a force of F/3.
Doubling a charge Q to 2Q reduces the electric field measured at double the distance from E to E/2.

Electric Flux

A charge Q at the center of a sphere generates a constant electric flux ΦE, which remains unchanged when the sphere's radius is doubled.

Phase Changes and Efficiency

The process of freezing 250 g of water produces multiple truths regarding energy transformations.
Increasing the efficiency of a Carnot engine is most effective when reducing the cold reservoir temperature by ΔT.

Efficiency of Heat Engines

The thermal efficiency formula e = W/Qh applies universally to all types of heat engines.

Electric Field Measurements

An electric field of 4.00 N/C occurs at approximately 3.4 m from a 5.00 nC charge.
A 9.6-μC charge at the center of a cube generates an electric flux of 1.80E5 N-m²/C through one face.

Charge Calculations

A -5.00-nC charge on the x-axis, with a second charge at -0.600 m, results in an overall electric field of 45.0 N/C at the origin, indicating a +5.5E-10 C charge for Q.

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Explore the fundamental concepts of charge, electrical forces, and thermodynamic principles in this quiz. Test your understanding of laws related to energy conservation, entropy, and electric fields. Perfect for students studying physics to deepen their comprehension of these essential topics.