1. What is the difference between isometric and isotonic muscle contractions?

A. Isometric involves movement, while isotonic does not.
B. Isotonic involves shortening of muscle, while isometric maintains length.
C. Isometric uses more energy, while isotonic uses less.
D. Isotonic involves smooth muscle, while isometric involves skeletal muscle.

Correct answer: B

Rationale: The correct answer is B: "Isotonic involves shortening of muscle, while isometric maintains length." Isometric contractions occur when the muscle generates force without changing its length, such as holding a weight in a fixed position. On the other hand, isotonic contractions involve the muscle changing length, either by shortening (concentric contraction) or lengthening (eccentric contraction) while generating force. Understanding this distinction is crucial for grasping the different types of muscle contractions and their effects on the body during exercise and movement.

2. How do you spell the past participle of the verb "lie" (to recline)?

A. lied
B. lain
C. lay
D. lying

Correct answer: B

Rationale: The past participle of "lie" (to recline) is "lain," not "lied," which is the past tense.

3. A pressure vessel has a cylindrical body (diameter 10cm, height 20cm) with hemispherical ends (same diameter as the cylinder). What is its total surface area?

A. 785 sq cm
B. 1130 sq cm
C. 1570 sq cm
D. 2055 sq cm

Correct answer: D

Rationale: Calculate the surface area of the cylinder (base + lateral surface) and two hemispheres. Add them all up for the total surface area.

4. During inhalation, which muscle contracts to increase the volume of the thoracic cavity, allowing air to flow into the lungs?

A. Diaphragm
B. Intercostal muscles
C. Abdominal muscles
D. Pectoral muscles

Correct answer: A

Rationale: The correct answer is A: Diaphragm. During inhalation, the diaphragm contracts and moves downward, increasing the volume of the thoracic cavity. This action creates a pressure difference between the lungs and the atmosphere, causing air to flow into the lungs. The intercostal muscles also play a role by expanding the ribcage, but the primary muscle responsible for increasing thoracic cavity volume during inhalation is the diaphragm. Abdominal muscles are involved in exhalation by contracting to push the diaphragm up, reducing thoracic cavity volume. Pectoral muscles are located in the chest and are not directly involved in the breathing process.

5. What is the principle behind optical fibers used in communication?

A. Reflection of light within the fiber
B. Refraction of light due to different densities within the fiber
C. Total internal reflection guiding light through the fiber core
D. Diffraction of light around bends in the fiber

Correct answer: C

Rationale: Optical fibers used in communication rely on the principle of total internal reflection guiding light through the fiber core. When light enters the fiber at a certain angle, it reflects off the boundary between the core and cladding, ensuring that the light remains trapped within the core and travels along the fiber without significant loss of signal. This total internal reflection allows for efficient transmission of light signals over long distances in optical communication systems.

6. What is the primary factor that determines whether a solute will dissolve in a solvent?

A. Temperature
B. Pressure
C. Molecular structure
D. Particle size

Correct answer: c

Rationale: The molecular structure of the solute and solvent plays a key role in determining solubility. The other choices may influence solubility but are not the primary determining factor.