define power in physics

ATI TEAS 7

TEAS 7 practice test free science

1. What is the definition of power in physics?

A. The rate of change of energy
B. The rate of doing work or transferring energy
C. The measure of an object's potential energy
D. The force exerted on an object

Correct answer: B

Rationale: The correct answer is B: 'The rate of doing work or transferring energy.' Power in physics is defined as the rate at which work is done or energy is transferred. It is a measure of how quickly energy is transferred or converted. Power is not the same as energy itself but rather how fast energy is being transferred or converted. Choice A, 'The rate of change of energy,' is incorrect because power is about the rate of work or energy transfer, not just the change in energy. Choice C, 'The measure of an object's potential energy,' is incorrect as power is not a measure of potential energy but rather the rate of energy transfer. Choice D, 'The force exerted on an object,' is incorrect as power is related to work and energy transfer, not just force exerted.

2. Imagine you have an element with atomic number 11 and mass number 23. How many neutrons does it have?

A. 11
B. 12
C. 23
D. 21

Correct answer: B

Rationale: - The atomic number (Z) of an element is the number of protons in its nucleus. In this case, the element has an atomic number of 11. - The mass number (A) of an element is the sum of its protons and neutrons. Given that the mass number is 23 and the atomic number is 11, we can calculate the number of neutrons by subtracting the atomic number from the mass number: Neutrons = Mass number - Atomic number = 23 - 11 = 12. - Therefore, the element with atomic number 11 and mass number 23 has 12 neutrons.

3. Which of the following is an example of a decomposition reaction?

A. 2H2 + O2 → 2H2O
B. CaCO3 → CaO + CO2
C. 2Na + Cl2 → 2NaCl
D. N2 + 3H2 → 2NH3

Correct answer: B

Rationale: A decomposition reaction involves a single compound breaking down into two or more simpler substances. In option B, CaCO3 breaks down into CaO and CO2, making it an example of a decomposition reaction. Options A, C, and D involve different types of chemical reactions such as synthesis, combination, and combustion, respectively. Option A represents a synthesis reaction, where two elements combine to form a compound. Option C demonstrates a combination reaction, where two elements combine to form a compound. Option D is an example of a synthesis reaction, where two reactants combine to form a single compound. It is important to recognize the specific characteristics of each type of chemical reaction to identify the correct example of decomposition reaction, where a compound breaks down into simpler products.

4. How many molecules of NADPH and ATP are required to reduce 6 molecules of CO2 to glucose via photosynthesis?

A. 6 NADPH and 9 ATP
B. 12 NADPH and 18 ATP
C. 18 NADPH and 24 ATP
D. 24 NADPH and 36 ATP

Correct answer: B

Rationale: During photosynthesis, 12 molecules of NADPH and 18 molecules of ATP are required to reduce 6 molecules of CO2 to glucose. NADPH and ATP are essential energy carriers in the process of photosynthesis. Choice A is incorrect because it underestimates the required molecules of both NADPH and ATP. Choices C and D overestimate the number of molecules needed, making them incorrect answers.

5. In which regions of the digestive system is amylase produced?

A. pancreas and salivary glands
B. gall bladder and salivary glands
C. gall bladder and liver
D. pancreas and liver

Correct answer: A

Rationale: Amylase is an enzyme that breaks down carbohydrates into smaller sugars. It is produced in the pancreas and salivary glands. The salivary glands release amylase into the mouth during chewing, where it initiates the breakdown of carbohydrates. The pancreas also secretes amylase into the small intestine to further assist in carbohydrate digestion. Choices B, C, and D are incorrect as the gall bladder does not produce amylase, and the liver's primary function is not the production of amylase for carbohydrate breakdown.