HESI A2 Physics Practice Test

Correct Answer: A

Rationale: When a dielectric material is inserted between the plates of a charged capacitor, the capacitance will increase. This is because the dielectric reduces the electric field between the plates, which allows for more charge to be stored for a given potential difference. The dielectric polarization enhances the capacitance. The other choices are incorrect because capacitance does not decrease or remain the same when a dielectric is added, and it is not unpredictable as the relationship between capacitance and dielectric constant is well-defined.

Correct Answer: D

Rationale: To calculate momentum, we use the formula: momentum = mass x velocity. Given mass = 5 kg and velocity = 5 m/s, the momentum is 5 kg x 5 m/s = 25 kg⋅m/s. Therefore, choice D (25 kg⋅m/s) is the correct answer. Choice A (10 kg⋅m/s) is incorrect as it doesn't account for both mass and velocity. Choice B (16.2 km/h) is incorrect as it is a unit conversion for speed, not momentum. Choice C (24.75 kg⋅m/s) is incorrect as it doesn't match the calculated momentum value.

Correct Answer: D

Rationale: Step-by-step rationale: 1. In an isothermal process, temperature remains constant. 2. Compressing a gas increases its pressure. 3. Work is done on the gas by the surroundings in compression. 4. As work is done on the gas, its internal energy decreases. Therefore, choice D is correct. Summary: A: Incorrect; Internal energy does not increase when work is done on the gas. B: Incorrect; Internal energy does not decrease when work is done on the gas. C: Incorrect; Work is done by the surroundings on the gas, not vice versa.

Correct Answer: B

Rationale: The correct answer is B because in a transverse wave, particles of the medium move perpendicular to the direction of energy transfer. Therefore, when the wave moves from north to south, the particles move both northward and southward. Choice A is incorrect because particles don't only move in one direction. Choices C and D are incorrect as transverse waves do not cause particle movement in the east-west direction.

Correct Answer: A

Rationale: The correct answer is A: 0 watts. When an appliance draws 0 amperes, it means no current flows, so no power is consumed. Power (in watts) is calculated as Voltage x Current. Since the current is 0, the power consumed is 0 watts. Choice B, C, and D are incorrect because they assume there is power consumption when there is no current flowing.