the speed of light in a vacuum is measured in units of

ATI TEAS 7

ati teas 7 science

1. In which units is the speed of light in a vacuum measured?

A. Meters per second
B. Hertz
C. Candela
D. Newton

Correct answer: A

Rationale: The speed of light in a vacuum is commonly measured in units of meters per second. This is because the speed of light is approximately 299,792,458 meters per second in a vacuum, as defined by the International System of Units (SI). The speed of light is a measure of distance covered by light in a given time, hence it is expressed in meters per second. Choices B, C, and D are incorrect. Hertz is a unit of frequency, Candela is a unit of luminous intensity, and Newton is a unit of force. None of these units are relevant for measuring the speed of light, making 'Meters per second' the correct unit of measurement for the speed of light.

2. What is the oxidation state of carbon in CH4?

A. +1
B. -1
C. +2
D. -4

Correct answer: D

Rationale: In CH4 (methane), carbon is bonded to four hydrogen atoms. Hydrogen has an oxidation state of +1. Since the overall charge of CH4 is 0, the oxidation state of carbon must be -4 to balance the charges. Each hydrogen contributes an oxidation state of +1, resulting in a total of +4 from hydrogen atoms. To achieve a total oxidation state of 0 for the molecule, carbon must have an oxidation state of -4 to offset the contribution from hydrogen. Therefore, the correct answer is -4. Choices A, B, and C are incorrect: +1 is the oxidation state of hydrogen, -1 is not the oxidation state of carbon in methane, and +2 is not the correct oxidation state of carbon in CH4.

3. What is the process by which a population gradually loses genetic variation?

A. Founder effect
B. Bottleneck effect
C. Gene flow
D. Speciation

Correct answer: B

Rationale: A) Founder effect: This occurs when a small group of individuals establishes a new population, leading to a loss of genetic variation compared to the original population. It does not necessarily result in a gradual loss of genetic variation in an existing population. B) Bottleneck effect: This process occurs when a population is drastically reduced in size, leading to a significant loss of genetic variation due to the limited number of individuals contributing to the gene pool. The reduced genetic diversity can have long-term effects on the population's ability to adapt to environmental changes. C) Gene flow: This refers to the movement of genes between populations, which can introduce new genetic variation and prevent populations from diverging. Gene flow does not lead to a gradual loss of genetic variation within a population. D) Speciation: This is the process by which new species evolve from existing species, often involving the accumulation of genetic differences that l

4. Which of the following is the carbohydrate monomer?

A. Disaccharide
B. Lactose
C. Monosaccharide
D. Thymine

Correct answer: C

Rationale: The correct answer is C: Monosaccharide. Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar unit. They are considered the carbohydrate monomers from which larger carbohydrates like disaccharides (composed of two sugar units) and polysaccharides (containing multiple sugar units) are built. Choices A and B, Disaccharide and Lactose, are not monomers but rather specific types of carbohydrates made up of multiple sugar units. Choice D, Thymine, is a nitrogenous base present in DNA and RNA, not a carbohydrate monomer.

5. An investigator wishes to test the effect of temperature on the durability of a certain material. He places five blocks of this material in a sunny area in a meadow and five more in a cold area high in the mountains. He then monitors them over time. What is the main problem with this experiment?

A. Ten subjects are far too small a number to obtain effective results.
B. It is impossible to control for the fact that the blocks in the mountains were placed later.
C. There are too many variables that are not being controlled for.
D. Nothing is wrong with this experiment; this demonstrates good experimental procedure.

Correct answer: C

Rationale: The main problem with this experiment is that there are too many variables that are not being controlled for. The investigator is only changing one variable (temperature) while there are other variables at play such as humidity, exposure to light, and potential differences in the material itself. Without controlling or accounting for these additional variables, it would be difficult to determine if any observed differences in durability are solely due to temperature. Choice A is incorrect because the issue is not solely about the number of subjects but about the lack of control over variables. Choice B is not the main problem as the order of placement may not significantly impact the results. Choice D is incorrect as the experiment lacks proper control over variables, which is a crucial aspect of good experimental procedure.