in an adiabatic process there is

HESI A2

HESI A2 Physics

1. In an adiabatic process, there is:

A. No heat transfer (Q = 0) between the system and the surroundings.
B. Isothermal compression or expansion (constant temperature).
C. Constant pressure throughout the process (isobaric process).
D. No change in the system's internal energy (energy is conserved according to the first law).

Correct answer: A

Rationale: In an adiabatic process, choice A is correct because adiabatic processes involve no heat transfer between the system and its surroundings (Q = 0). This lack of heat transfer is a defining characteristic of adiabatic processes. Choices B, C, and D do not accurately describe an adiabatic process. Choice B refers to an isothermal process where temperature remains constant, not adiabatic. Choice C describes an isobaric process with constant pressure, not specific to adiabatic processes. Choice D mentions the conservation of energy but does not directly relate to the absence of heat transfer in adiabatic processes.

2. A box is moved by a 15 N force over a distance of 3 m. What is the amount of work that has been done?

A. 5 W
B. 5 N⋅m
C. 45 W
D. 45 N⋅m

Correct answer: D

Rationale: Work done is calculated using the formula: Work = Force x Distance. In this case, the force applied is 15 N and the distance covered is 3 m. Thus, work done = 15 N x 3 m = 45 N⋅m. Therefore, the correct answer is 45 N⋅m. Choice A (5 W) is incorrect because work is measured in joules (J) or newton-meters (N⋅m), not in watts (W). Choice B (5 N⋅m) is incorrect as it miscalculates the work by not multiplying the force by the distance. Choice C (45 W) is incorrect because work is not measured in watts (W) but in newton-meters (N⋅m).

3. What is the SI unit for quantifying the transfer of energy due to an applied force?

A. Newton (N)
B. Meter per second (m/s)
C. Joule (J)
D. Kilogram (kg)

Correct answer: C

Rationale: The correct answer is C: Joule (J). The joule is the SI unit used to quantify the transfer of energy due to an applied force. It is defined as the work done when a force of one newton is applied over a distance of one meter. Newton (N) is the unit of force, not energy transfer. Meter per second (m/s) is the unit of speed, not energy transfer. Kilogram (kg) is the unit of mass, not energy transfer. Therefore, the correct unit for quantifying the transfer of energy due to an applied force is the joule (J).

4. If a wave has a frequency of 60 hertz, which of the following is true?

A. It completes one cycle per minute.
B. It measures 60 m from crest to crest.
C. It completes 60 cycles per second.
D. It measures 60 m from crest to trough.

Correct answer: C

Rationale: The frequency of a wave is the number of cycles it completes in one second. A wave with a frequency of 60 hertz completes 60 cycles per second. Therefore, choice C is correct. Choice A is incorrect because a frequency of 60 hertz means 60 cycles per second, not per minute. Choice B is incorrect as the frequency of the wave does not determine the distance from crest to crest. Choice D is also incorrect as the frequency does not relate to the distance from crest to trough.

5. A system undergoes an isobaric process (constant pressure). In this process, the work done (W) by the system is:

A. Zero, if the volume change (ΔV) is zero.
B. Positive and equal to the pressure multiplied by the volume change (W = PΔV).
C. Negative and equal to the pressure multiplied by the volume change.
D. Independent of the pressure or volume change.

Correct answer: B

Rationale: In an isobaric process (constant pressure), the work done is given by the formula W = PΔV, where P is the pressure and ΔV is the change in volume. If the volume does not change, the work done is zero, not negative. Choice A is incorrect as it states the work done is zero when the volume change is zero, which is the correct condition for zero work. Choice C is incorrect as it incorrectly suggests that the work done is negative in an isobaric process. Choice D is incorrect as the work done in an isobaric process is indeed dependent on the volume change and pressure.