Nursing Elites

1. A 5-cm candle is placed 20 cm away from a concave mirror with a focal length of 15 cm. About what is the image height of the candle in the mirror?

• A. 30.5 cm
• B. 15.625 cm
• C. −15 cm
• D. −30.5 cm

Correct answer: B

Rationale: The magnification formula for a mirror is given by M = -f / (f - d), where f is the focal length of the mirror, and d is the object distance from the mirror. Using the mirror equation and magnification formula, the image height is found to be negative because it is inverted. Plugging in the values (f = 15 cm, d = 20 cm) into the formula gives M = -15 / (15 - 20) = -15 / -5 = 3. The negative sign indicates that the image is inverted. The image height is then calculated by multiplying the magnification by the object height: 3 * 5 cm = 15 cm. Therefore, the correct image height is approximately -15 cm. Choice A (30.5 cm) and Choice D (-30.5 cm) are incorrect as they do not consider the inversion of the image. Choice C (-15 cm) is also incorrect because it neglects the negative sign, which indicates the inversion of the image.

2. Amanda uses 100 N of force to push a lawnmower around her lawn. If she mows 20 rows measuring 30 meters each, how much work does she do?

• A. 3,000 N⋅m
• B. 6,000 N⋅m
• C. 60,000 N⋅m
• D. The answer cannot be determined from the information given.

Correct answer: C

Rationale: The work done by Amanda pushing the lawnmower is calculated by multiplying the force applied (100 N) by the distance over which the force is applied (the total distance mowed). Since Amanda mows 20 rows, each measuring 30 meters, the total distance mowed is 20 rows x 30 meters/row = 600 meters. Therefore, the work done is 100 N x 600 m = 60,000 N⋅m. Option A and B are incorrect as they do not account for the total distance mowed. Option D is incorrect as the work done can be accurately calculated based on the information provided.

3. Two balloons with charges of 5 μC each are placed 25 cm apart. What is the magnitude of the resulting repulsive force between them?

• A. 0.18 N
• B. 1.8 N
• C. 10−3 N
• D. 5 × 10−3 N

Correct answer: B

Rationale: To find the repulsive force between the two charges, we use Coulomb's law: F = k(q1 * q2) / r^2. Here, k is the Coulomb constant (8.99 x 10^9 Nm^2/C^2), q1 and q2 are the charges (5 μC each), and r is the distance between the charges (25 cm = 0.25 m). Substituting these values into the formula: F = (8.99 x 10^9 Nm^2/C^2)(5 x 10^-6 C)(5 x 10^-6 C) / (0.25 m)^2. Calculating this gives F = 1.8 N. Therefore, the magnitude of the resulting repulsive force between the two balloons is 1.8 N. Choice A, C, and D are incorrect as they do not correctly calculate the force using Coulomb's law.

4. In Einstein’s mass-energy equation, what is represented by c?

• A. Distance in centimeters
• B. The speed of light
• C. Degrees Celsius
• D. Centrifugal force

Correct answer: B

Rationale: In Einstein's mass-energy equation, E=mc^2, the symbol 'c' represents the speed of light in a vacuum, which is approximately equal to 3.00 x 10^8 meters per second. This equation demonstrates the equivalence of energy (E) and mass (m) and is a fundamental concept in the theory of relativity. Choice A is incorrect as 'c' does not represent distance in centimeters. Choice C is incorrect as 'c' does not represent degrees Celsius. Choice D is incorrect as 'c' does not represent centrifugal force.

5. What is the phenomenon by which light bends as it passes through a prism known as?

• A. Reflection
• B. Electrical conduction
• C. Diffraction
• D. Refraction

Correct answer: D

Rationale: Refraction is the phenomenon by which light bends as it passes through a prism or any other medium boundary. When light transitions from one medium to another, such as air to glass in the case of a prism, it changes speed and direction due to the change in the medium's refractive index. This change in speed causes the light to bend. Reflection, on the other hand, is the bouncing back of light when it hits a surface. Diffraction refers to the bending of light around obstacles or through narrow openings. Electrical conduction involves the movement of electrically charged particles through a conductor, which is unrelated to the bending of light.

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