Nursing Elites

1. When light travels from air into a denser medium like glass, its speed:

• A. Increases
• B. Decreases
• C. Remains constant
• D. Becomes unpredictable

Correct answer: B

Rationale: When light travels from air into a denser medium like glass, its speed decreases. This is because the higher refractive index of the denser medium causes light to slow down as it propagates through the medium. Choice A is incorrect because the speed of light decreases in a denser medium. Choice C is incorrect because the speed of light changes when it enters a denser medium. Choice D is incorrect because the change in speed is predictable based on the refractive index of the medium.

2. Bernoulli's principle for an incompressible, inviscid fluid in steady flow states that the mechanical energy, consisting of:

• A. Pressure (P) only, remains constant along a streamline.
• B. Velocity (v) only, remains constant along a streamline.
• C. P + ½ρv² (total mechanical energy), remains constant along a streamline
• D. Density (ρ) only, remains constant along a streamline.

Correct answer: C

Rationale: Bernoulli's principle states that the sum of pressure energy (P), kinetic energy per unit volume (½ρv²), and potential energy per unit volume remains constant along a streamline in an incompressible, inviscid fluid. This means the total mechanical energy of the fluid is conserved, making Choice C the correct answer. Choices A, B, and D are incorrect because Bernoulli's principle involves the conservation of the total mechanical energy, not just pressure, velocity, or density alone.

3. What does Coulomb’s law relate to?

• A. electrostatic interaction
• B. rigid body motion
• C. heat conduction
• D. universal gravitation

Correct answer: A

Rationale: Coulomb's law is a fundamental principle in physics that deals with the electrostatic interaction between charged particles. It states that the force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. This law is crucial in understanding and predicting the behavior of electrically charged objects. Choices B, C, and D are incorrect because Coulomb's law specifically focuses on electrostatic interactions between charges, not rigid body motion, heat conduction, or universal gravitation.

4. A concave mirror with a focal length of 2 cm forms a real image of an object at an image distance of 6 cm. What is the object's distance from the mirror?

• A. 3 cm
• B. 6 cm
• C. 12 cm
• D. 30 cm

Correct answer: B

Rationale: The mirror formula, 1/f = 1/do + 1/di, can be used to solve for the object distance. Given that the focal length (f) is 2 cm and the image distance (di) is 6 cm, we can substitute these values into the formula to find the object distance. Plugging in f = 2 cm and di = 6 cm into the formula gives us 1/2 = 1/do + 1/6. Solving for do, we get do = 6 cm. Therefore, the object's distance from the mirror is 6 cm. Choice A (3 cm), Choice C (12 cm), and Choice D (30 cm) are incorrect distances as the correct object distance is determined to be 6 cm.

5. Jack stands in front of a plane mirror. If he is 5 feet away from the mirror, how far away from Jack is his image?

• A. 2.5 feet
• B. 3 feet
• C. 4.5 feet
• D. 5 feet

Correct answer: D

Rationale: When Jack stands in front of a plane mirror, his image appears the same distance behind the mirror as Jack is in front of it. Therefore, if Jack is 5 feet away from the mirror, his image will also appear 5 feet behind the mirror. The total distance from Jack to his image is the sum of these distances, which equals 10 feet. Choices A, B, and C are incorrect because the image distance is not half of the total distance but the same as the object's distance from the mirror.

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