HESI Exams Quizlet Physics

Correct Answer: A

Rationale: To find the current flowing through the flashlight, use Ohm's Law: Current (I) = Voltage (V) / Resistance (R). Given V=3V and R=60Ω, I = 3V / 60Ω = 0.05 amp (A). This is the correct answer. Choice B, 0.5 amp, is incorrect as it does not match the calculated value. Choice C and D, 1.8 amp and 18 amp respectively, are also incorrect as they are significantly higher than the calculated current value and would require a much higher voltage source.

Correct Answer: A

Rationale: The correct answer is A: Q = cΔT. This equation represents the definition of specific heat capacity, where Q (heat transfer) is equal to the product of c (specific heat capacity) and ΔT (temperature change) for a unit mass of the material. This equation is derived from the formula for heat transfer, Q = mcΔT, by dividing both sides by mass 'm'. Therefore, the correct equation is Q = cΔT. Summary of other choices: B: Q = mcΔT - This is the formula for total heat transfer, not specific heat capacity. C: Q = c / mΔT - This equation does not accurately represent the relationship between specific heat capacity, heat transfer, temperature change, and mass. D: Q = ΔT / mc - This equation is not a correct representation of specific heat capacity and does not follow the standard formula.

Correct Answer: B

Rationale: The correct answer is B (15.625 cm). To calculate the image height using mirror formula (1/f = 1/v + 1/u), first find the object distance (u) which is -20 cm (since object is placed on the same side as focal point, it is negative). Then, solve for image distance (v) by substituting u and f values. Next, use magnification formula (m = -v/u) to find the magnification factor. Finally, multiply the object height by the magnification factor to get the image height, which is 15.625 cm. Choice A (30.5 cm) is incorrect as it is double the correct answer. Choice C (-15 cm) and choice D (-30.5 cm) are incorrect as the negative sign indicates an inverted image, but in this case, the image is upright.

Correct Answer: A

Rationale: The correct answer is A: 10 m/s. Velocity is calculated by dividing the distance traveled by the time taken. In this case, velocity = 100m / 10s = 10 m/s. Choice B, 90 m/s, is incorrect because it is not the accurate calculation. Choice C, 110 m/s, and choice D, 1,000 m/s, are both incorrect as they do not align with the correct formula for calculating velocity. The key is to remember that velocity is a vector quantity that includes both speed and direction, and in this case, we are only concerned with the speed of the object, making choice A the correct answer.

Correct Answer: D

Rationale: The correct answer is D: To allow the circuit to open and close. A switch in a circuit functions by either completing or interrupting the flow of current. When the switch is closed, it provides a path for the current to flow, allowing the circuit to be operational. Conversely, when the switch is opened, it breaks the circuit, halting the flow of current. This on-off capability of a switch enables control over the circuit, making it a fundamental component in regulating the flow of electricity. Choices A, B, and C are incorrect because a switch does not reverse the direction of current, increase voltage, or alter the resistance of wires in a circuit.