1. Delta waves, associated with deep sleep, exhibit what frequency range?

A. 0.5-4 Hz
B. 4-8 Hz
C. 8-13 Hz
D. 13-30 Hz

Correct answer: A

Rationale: Delta waves are slow brainwaves that are typically associated with deep sleep stages, such as stages 3 and 4 of non-REM sleep. These waves have a frequency range of 0.5-4 Hz, making option A the correct answer. During deep sleep, the brain slows down significantly, and delta waves are prominent on an electroencephalogram (EEG). The frequency range of 4-8 Hz corresponds to theta waves, which are more commonly observed during light sleep or drowsiness. Alpha waves fall within the 8-13 Hz range and are typically seen when an individual is awake but relaxed. Beta waves, ranging from 13-30 Hz, are associated with alertness and active thinking. Therefore, option A is the correct choice for delta waves, reflecting their slow frequency characteristic during deep sleep.

2. A car accelerates from rest. What happens to its kinetic energy and work done on it?

A. Both kinetic energy and work done increase
B. Kinetic energy increases, but work done remains constant.
C. Work done increases, but kinetic energy remains constant.
D. Both kinetic energy and work done remain constant.

Correct answer: A

Rationale: During acceleration, the car's speed increases, leading to rising kinetic energy. Simultaneously, the force applied to accelerate the car does work on it, increasing the work done.

3. Which term describes the quantity of matter in an object and is measured in kilograms or grams?

A. Weight
B. Mass
C. Volume
D. Density

Correct answer: B

Rationale: Mass is the term that describes the quantity of matter in an object. It is typically measured in kilograms or grams. Weight, on the other hand, is the force of gravity acting on an object and is measured in newtons. Volume is the amount of space an object occupies, typically measured in cubic units such as cubic meters or cubic centimeters. Density is the mass of an object per unit volume and is measured in units such as kilograms per cubic meter.

4. What happens to the concentration of hydrogen ions ($[H^+]$) in a solution as the pH increases?

A. Increases
B. Decreases
C. Remains constant
D. Becomes neutral

Correct answer: B

Rationale: As the pH increases, the concentration of hydrogen ions decreases. The relationship is inversely proportional

5. What is the difference between a pure substance and a mixture?

A. Pure substances have fixed composition, mixtures don't.
B. Mixtures have fixed composition, pure substances don't
C. Pure substances are always solids, mixtures can be any state
D. Pure substances are always elements, mixtures are always compounds

Correct answer: A

Rationale: Rationale: - Pure substances have a definite and constant composition, meaning they are made up of only one type of atom or molecule. This composition does not vary. - Mixtures, on the other hand, are composed of two or more substances physically combined. The components of a mixture can be present in varying proportions, leading to a variable composition. - Option A correctly distinguishes between pure substances and mixtures based on the fixed composition of pure substances and the variable composition of mixtures.