Regents Physics 3 — Questions and Answers
Question 1: A 2 kg mass is lifted 5 m vertically. What is the gravitational potential energy gained? (g = 9.8 m/s²)
- 9.8 J
- 49 J
- 98 J (Correct answer)
- 196 J
Correct answer: 98 J
PE = mgh = 2 × 9.8 × 5 = 98 J.
Question 2: Which type of electromagnetic radiation has the highest frequency?
- Radio waves
- Visible light
- X-rays
- Gamma rays (Correct answer)
Correct answer: Gamma rays
Gamma rays have the highest frequency (and shortest wavelength) in the electromagnetic spectrum.
Question 3: A 1,500 W hair dryer is used for 2 minutes. How much electrical energy is consumed?
- 750 J
- 3,000 J
- 180,000 J (Correct answer)
- 3,000 W
Correct answer: 180,000 J
E = P × t = 1,500 W × 120 s = 180,000 J.
Question 4: In a series circuit with three resistors (2 Ω, 3 Ω, and 5 Ω), what is the total resistance?
- 0.97 Ω
- 5 Ω
- 10 Ω (Correct answer)
- 30 Ω
Correct answer: 10 Ω
In a series circuit, total resistance = R₁ + R₂ + R₃ = 2 + 3 + 5 = 10 Ω.
Question 5: A sound wave travels from air into water. Which property of the wave remains unchanged?
- Speed
- Wavelength
- Frequency (Correct answer)
- Amplitude
Correct answer: Frequency
Frequency is determined by the source and remains constant when a wave crosses a boundary; speed and wavelength change.
Question 6: Which of the following is an example of nuclear fission?
- Hydrogen nuclei fusing to form helium in the Sun
- A uranium nucleus splitting into smaller nuclei (Correct answer)
- An electron emitted during beta decay
- A proton gaining a neutron
Correct answer: A uranium nucleus splitting into smaller nuclei
Nuclear fission involves a heavy nucleus (like uranium) splitting into smaller fragments, releasing large amounts of energy.
Question 7: A block slides down a frictionless ramp. At the bottom its kinetic energy equals 200 J. What was its gravitational potential energy at the top?
- 0 J
- 100 J
- 200 J (Correct answer)
- 400 J
Correct answer: 200 J
On a frictionless ramp, all gravitational PE converts to KE, so PE at top = KE at bottom = 200 J.
Regents Physics 3
A 2 kg mass is lifted 5 m vertically.
What is the gravitational potential energy gained? (g = 9.8 m/s²)