Nursing Elites

1. Which of the following materials has the lowest density?

• A. Water
• B. Cork
• C. Aluminum
• D. Steel

Correct answer: B

Rationale: Cork has the lowest density among the given options. Cork is a lightweight material derived from the bark of cork oak trees and is known for its low density, making it float on water. Water, aluminum, and steel have higher densities compared to cork. Water is denser than cork because it has a consistent density of 1 g/cm³. Aluminum and steel are metals with much higher densities due to their atomic structures, making them denser than cork.

2. In a static fluid, pressure (P) at a depth (h) is governed by the hydrostatic equation:

• A. P = ρgh
• B. P = γh
• C. P = μgh
• D. P = bh

Correct answer: A

Rationale: The correct formula for the pressure at a certain depth in a fluid according to the hydrostatic equation is P = ρgh. Here, ρ represents the fluid's density, g is the gravitational acceleration, and h is the depth. This formula shows that pressure increases linearly with the density of the fluid, the acceleration due to gravity, and the depth. Choices B, C, and D are incorrect because they do not accurately represent the relationship between pressure, density, gravitational acceleration, and depth in a static fluid.

3. Which conclusion can be drawn from Ohm’s law?

• A. Voltage and current are inversely proportional when resistance is constant.
• B. The ratio of the potential difference between the ends of a conductor to current is a constant, R.
• C. Voltage is the amount of charge that passes through a point per second.
• D. Power (P) can be calculated by multiplying current (I) by voltage (V).

Correct answer: B

Rationale: Ohm's law states that the ratio of the potential difference (voltage) between the ends of a conductor to the current flowing through it is a constant. Mathematically, this is represented as V = I x R, where V is voltage, I is current, and R is the constant resistance. Therefore, the correct conclusion that can be drawn from Ohm's law is that the ratio of the potential difference between the ends of a conductor to current is a constant, denoted as R. This relationship is fundamental to understanding the behavior of electrical circuits and the effect of resistance on voltage and current. Choice A is incorrect because Ohm's law actually states that voltage and current are directly proportional when resistance is constant. Choice C is incorrect because voltage is not the amount of charge that passes through a point per second; rather, it is the electric potential energy per unit charge. Choice D is incorrect because although power (P) can be calculated by multiplying current (I) by voltage (V), this is not a conclusion directly drawn from Ohm's law.

4. Which characteristic does a transverse wave not have?

• A. a compression
• B. an amplitude
• C. a frequency
• D. a wavelength

Correct answer: A

Rationale: A transverse wave does not have a compression because transverse waves move perpendicular to the direction of the oscillation. In a transverse wave, the particles move up and down, causing crests and troughs, without creating compressions. Compressions are characteristic of longitudinal waves where the particles move parallel to the direction of the wave. The other choices (B, C, and D) are characteristics that transverse waves possess: amplitude is the maximum displacement of a wave from its equilibrium position, frequency is the number of complete oscillations a wave makes in a given time, and wavelength is the distance between two consecutive points in a wave that are in the same phase.

5. How might the energy use of an appliance be expressed?

• A. Power = energy × time
• B. Time + energy = power
• C. Energy = power × time
• D. Energy/power = time

Correct answer: C

Rationale: The energy use of an appliance can be expressed using the formula Energy = Power × Time. In this formula, Energy represents the amount of electricity consumed by the appliance, Power indicates the rate at which the appliance uses electricity (measured in watts), and Time represents the duration for which the appliance is being used (measured in hours). By multiplying the power rating of the appliance by the time it is in use, one can calculate the total energy consumed. Option C is the correct choice because it accurately represents the relationship between power, time, and energy. Choices A, B, and D present incorrect representations of the relationship between energy, power, and time, making them wrong answers.

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