10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The TX PACT 739 exam has 125 questions and runs 3 hours 45 minutes.
These 10 free TX PACT 739 questions are organized by exam domain, so you can see how each part of the TX PACT: Physics: Grades 7-12 (739) blueprint is tested. Reveal the answer and explanation under each question.
Inserting a calibrated ammeter in series with a battery and resistor produces a stable current slightly below the prediction made for an ideal ammeter. Connections are correct, the source voltage is stable, and all components operate within their ratings. Which response to this discrepancy is justified?
Correct answer: A - Include the real ammeter's small series resistance in the prediction.
During a laboratory investigation, a teacher notices exposed copper in the energized mains cord of a power supply. Water has spilled beside the damaged section. A marked power cutoff is dry and reachable without entering the wet area. What should the teacher do first?
Correct answer: B - Keep everyone clear and use the safe cutoff to isolate power; withdraw the damaged equipment from use.
A cart's velocity-time graph is a straight line that starts above the time axis and ends equally far below it, crossing the axis halfway through the interval. What does the graph establish about the cart's overall motion?
Correct answer: C - It returns to its starting position after traveling a nonzero distance.
In steady, incompressible flow, water moves faster at a lower point on a streamline than at an upper point. Viscous losses are negligible, and no pump or turbine acts between the points. Must the lower point have greater static pressure?
Correct answer: C - It depends on the competing effects of the speed increase and elevation decrease.
Two identical pucks collide on a horizontal air table and stick together. Just before impact, one travels east at 2.0 m/s and the other north at 2.0 m/s. External impulse during the collision is negligible. The speed of the joined pucks' center of mass immediately after impact is closest to:
Correct answer: A - 1.4 m/s
What are the electric field and potential at the midpoint between two equal positive point charges in vacuum, taking the potential to be zero at infinity?
Correct answer: A - The field is zero; the potential is positive.
A fixed, unbroken horizontal copper ring sits in a uniform upward magnetic field. The previously steady field begins to weaken without reversing. Viewed from above, the induced conventional current is:
Correct answer: D - Counterclockwise, producing an upward magnetic field.
A guitar string's fundamental tone and a 440 Hz tuning fork produce four beats per second when sounded together. As the guitarist slowly increases the string tension, the beats initially become less frequent. Before the adjustment, the string's fundamental frequency was:
Correct answer: B - 436 Hz
A photoelectric experiment uses light above a metal's threshold frequency. The experimenter increases the light intensity while keeping its frequency, illuminated area, and surface conditions unchanged. Assume single-photon photoemission. The maximum collected photocurrent and stopping-potential magnitude should:
Correct answer: D - Increase and remain unchanged, respectively.
A well-stirred mixture of pure ice and water is heated gently at atmospheric pressure. The temperature probe stays near 0°C while the amount of ice steadily decreases. The goal is to record the complete melting process. How should the investigation proceed?
Correct answer: B - Continue heating and recording; absorbed energy melts the ice while the temperature stays near 0°C.
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