TEAS 7 practice test science

Correct Answer: D

Rationale: The P wave on an ECG represents the depolarization of the atria. This electrical activity initiates the contraction of the atria, allowing blood to be pumped into the ventricles. The P wave is the first positive deflection seen on the ECG and signifies the beginning of atrial depolarization, which is a critical step in the cardiac cycle. Choices A, B, and C are incorrect. Option A (The repolarization of the ventricles) is represented by the T wave on the ECG. Option B (The electrical conduction through the AV node) is not represented by the P wave but rather by the PR interval on the ECG. Option C (The contraction phase of the ventricles (systole)) is more related to the QRS complex on the ECG, which represents ventricular depolarization and contraction.

Correct Answer: B

Rationale: The correct answer is B: Interference. Interference is the term used to describe the phenomenon when two waves combine to form a new wave. When waves interact constructively or destructively, they interfere with each other, resulting in a new wave pattern. Choice A, Diffraction, refers to the bending of waves around obstacles, not the combination of waves. Choice C, Refraction, is the bending of waves as they pass from one medium to another, not the combination of waves. Choice D, Dispersion, is the separation of light into its different colors, not the combination of waves.

Correct Answer: B

Rationale: Photons are not charged particles; they are packets of energy that exhibit wave-particle duality, meaning they can behave as both particles and waves. While photons are part of the electromagnetic spectrum, they are not electromagnetic waves themselves but rather discrete energy packets. They are not always absorbed by matter; they can be reflected, transmitted, or scattered.

Correct Answer: B

Rationale: The amplitude of a wave is directly related to its intensity or loudness. In general, the larger the amplitude of a wave, the greater its intensity or loudness. This relationship is due to the fact that the amplitude of a wave represents the maximum displacement of particles in the medium from their rest position. The greater the displacement, the more energy the wave carries, leading to higher intensity or louder sound. Choice A is incorrect because the relationship between amplitude and intensity is direct, not inverse. Choice C is incorrect as there is a clear relationship between amplitude and intensity. Choice D is incorrect as amplitude primarily affects intensity or loudness, not frequency.

Correct Answer: C

Rationale: Elements in Group 18 (Noble gases) are generally unreactive because their outermost electron shells are completely filled. This results in high stability and low reactivity since they have achieved a full valence shell configuration, making them less likely to gain, lose, or share electrons with other atoms. The full valence shell configuration leads to a minimal tendency for these elements to form chemical bonds, hence exhibiting low reactivity. Choices A, B, and D are incorrect because high atomic masses, lack of valence electrons, and existing as single atoms do not directly contribute to the unreactivity of noble gases. It is the full valence shell configuration that is the primary reason for their inert nature.