the efficiency of a heat engine is defined as the ratio of the net work done wnet by the engine to the heat input qh from the hot reservoir the relat

HESI A2

HESI A2 Physics Practice Test

1. The efficiency (η) of a heat engine is defined as the ratio of the net work done (Wnet) by the engine to the heat input (Qh) from the hot reservoir. The relationship is expressed as:

A. η = Wnet / Qh
B. η = Qh / Wnet
C. η = Wnet x Qh
D. η = (Wnet + Qh) / 2

Correct answer: A

Rationale: The correct formula for efficiency (η) of a heat engine is η = Wnet / Qh. Efficiency is defined as the ratio of the net work done by the engine (Wnet) to the heat input from the hot reservoir (Qh). This formula shows how effectively the engine converts heat into useful work, making choice A the correct answer. Choices B, C, and D present incorrect relationships between efficiency, net work done, and heat input, leading to their incorrectness.

2. He tried to remember the names of all the people who were there that night.

A. that
B. who
C. which
D. whom

Correct answer: B

Rationale: In this context, 'who' is the correct relative pronoun to refer to people. 'That' is used for things, 'which' is used for animals or things, and 'whom' is an object pronoun, not needed in this sentence. Therefore, 'who' is the most appropriate choice.

3. Which word is used incorrectly? 'I did the work before he asked me to.'

A. did
B. work
C. asked
D. before

Correct answer: A

Rationale: The word 'did' is correctly used in the sentence to form the past tense of the verb 'do.' In this context, 'did' is the appropriate term. The other words in the sentence, 'work,' 'asked,' and 'before,' are all used correctly and do not represent an incorrect word choice. Therefore, 'did' is the only word that is not used incorrectly in the given sentence.

4. Ocean waves build during a storm until there is a vertical distance from the high point to the low point of 6 meters and a horizontal distance of 9 meters between adjacent crests. The waves hit the shore every 5 seconds. What is the speed of the waves?

A. 1.2 m/s
B. 1.8 m/s
C. 2.0 m/s
D. 2.4 m/s

Correct answer: B

Rationale: To find the speed of the waves, we use the formula: speed = wavelength / period. The wavelength is the horizontal distance between adjacent crests, which is 9 meters in this case. The period is the time it takes for one wave to pass a fixed point, given as 5 seconds. Therefore, speed = 9 meters / 5 seconds = 1.8 m/s. Choice A (1.2 m/s) is incorrect because it miscalculates the speed. Choice C (2.0 m/s) and Choice D (2.4 m/s) are incorrect as they do not correctly calculate the speed using the provided data.

5. What does Dilute mean?

A. To concentrate
B. To make a liquid less concentrated
C. To solidify
D. To evaporate

Correct answer: B

Rationale: The correct definition of dilute is to make a liquid less concentrated. When a substance is diluted, it means it has been mixed with another substance to reduce its strength or concentration. Option A, 'To concentrate,' is the opposite of dilute. Option C, 'To solidify,' means to make or become hard or solid, which is unrelated to diluting a liquid. Option D, 'To evaporate,' means to change from a liquid to a vapor, also unrelated to diluting a liquid. Therefore, the correct answer is B.