what is the doppler effect and how does it explain the shift in frequency of sound waves perceived by an observer

ATI TEAS 7

TEAS 7 science practice questions

1. What is the Doppler effect, and how does it explain the shift in frequency of sound waves perceived by an observer?

A. It affects light waves, not sound waves.
B. It's the change in wave speed due to medium density.
C. It's the perceived change in frequency due to relative motion.
D. It's the bending of waves due to different mediums.

Correct answer: C

Rationale: The Doppler effect is the perceived change in frequency of a wave due to relative motion between the source of the wave and the observer. This phenomenon is commonly observed with sound waves, where the pitch of a sound appears higher as the source moves towards the observer and lower as the source moves away. Option A is incorrect as the Doppler effect primarily applies to sound waves, not light waves. Option B is incorrect because the Doppler effect is not about the change in wave speed due to medium density but rather a change in perceived frequency. Option D is incorrect as it describes wave bending due to different mediums, which is not the primary concept behind the Doppler effect. Therefore, option C accurately describes the Doppler effect and its application to the shift in frequency of sound waves perceived by an observer.

2. Deuterium, a stable isotope of hydrogen, has a nucleus containing:

A. A single proton
B. A proton and a neutron
C. Two protons and an electron
D. Two neutrons

Correct answer: B

Rationale: Deuterium, as an isotope of hydrogen, has an atomic number of 1 and a mass number of 2. The nucleus of deuterium contains one proton (as in all hydrogen atoms) and one neutron, totaling 2 nucleons in the nucleus. Therefore, the correct answer is that deuterium's nucleus contains a proton and a neutron. Choices A, C, and D are incorrect. Deuterium is not just a single proton (A), doesn't have two protons and an electron (C), and doesn't contain two neutrons (D). The correct composition of deuterium's nucleus is one proton and one neutron.

3. What happens during expiration?

A. The diaphragm contracts and the thoracic cavity expands.
B. The diaphragm relaxes and the thoracic cavity contracts.
C. The thoracic cavity expands, increasing pressure.
D. The diaphragm relaxes and moves upward.

Correct answer: B

Rationale: The correct answer is B. During expiration, the diaphragm relaxes, causing the thoracic cavity to contract. As the thoracic cavity decreases in size, the pressure inside the lungs increases, leading to air flowing out of the lungs. This process helps to expel carbon dioxide-rich air from the body. Choices A, C, and D are incorrect. In choice A, the diaphragm contracting and the thoracic cavity expanding describes inspiration, not expiration. Choice C is incorrect because during expiration, the thoracic cavity actually decreases in size. Choice D is incorrect as the diaphragm moving upward is not a typical movement associated with expiration.

4. Which of the following is not a biological macromolecule?

A. Glycoproteins
B. DNA
C. Phospholipid
D. Glucose

Correct answer: D

Rationale: Glucose is a monosaccharide, which is a simple sugar and not a macromolecule. Glycoproteins, DNA, and phospholipids are all examples of biological macromolecules. Glycoproteins are proteins covalently bonded to carbohydrates, DNA is a nucleic acid, and phospholipids are lipids that contain a phosphate group.

5. Which of the following nucleic acids carries the genetic information copied from DNA to the ribosomes?

A. DNA
B. mRNA
C. rRNA
D. tRNA

Correct answer: B

Rationale: The correct answer is B: mRNA. Messenger RNA (mRNA) is responsible for carrying the genetic information copied from DNA to the ribosomes for protein synthesis. mRNA serves as a temporary copy of the genetic instructions stored in DNA and acts as a messenger between the nucleus and ribosomes in the cytoplasm where protein synthesis occurs. While rRNA (ribosomal RNA) and tRNA (transfer RNA) play essential roles in the process of translation at the ribosomes, mRNA is the nucleic acid directly involved in carrying the genetic code for protein synthesis. Therefore, choices A, C, and D are incorrect as DNA is the original genetic material, rRNA is a component of the ribosomes, and tRNA carries amino acids during protein synthesis, respectively.