Unit Checkpoint
Unit Summary
This checkpoint assesses your understanding of the entire Energy & Waves unit. Review the key concepts before attempting the assessment questions.
Topics Covered in This Unit
- Wave Properties: amplitude, wavelength, frequency, period, wave speed
- Electromagnetic Spectrum: radio waves through gamma rays
- Wave Calculations: v = fλ, T = 1/f, E = hf
- Lab Analysis: interpreting wave data and diagrams
- Claim-Evidence Writing: scientific argumentation about waves
Review Examples
Review these key examples before taking the checkpoint assessment.
Key Concept Review
Wave Equation: v = fλ (speed = frequency × wavelength)
EM Spectrum Order: Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma (increasing frequency and energy)
Mechanical vs. Electromagnetic: Mechanical waves need a medium; EM waves can travel through vacuum
✏️ Practice
Test your understanding with these practice questions.
Practice Questions
0/3 correctWhat is the scientific method's first step?
A hypothesis is:
Which is a property of matter?
Checkpoint Assessment
Complete these 10 questions to assess your mastery of the Energy & Waves unit.
Question 1: A wave has wavelength 2 m and frequency 170 Hz. What is its speed?
Answer: v = fλ = 170 Hz × 2 m = 340 m/s
Question 2: List the electromagnetic spectrum in order from lowest to highest frequency.
Answer: Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays, Gamma rays
Question 3: What is the difference between transverse and longitudinal waves?
Answer: In transverse waves, particles move perpendicular to wave direction (like light, water waves). In longitudinal waves, particles move parallel to wave direction (like sound).
Question 4: Why can astronauts not talk to each other in space without radios?
Answer: Sound is a mechanical wave that requires a medium. Space is a vacuum with no particles to transmit sound vibrations. Radio waves are electromagnetic and can travel through vacuum.
Question 5: Calculate the wavelength of a radio wave with frequency 100 MHz (10^8 Hz).
Answer: λ = c/f = (3 × 10^8 m/s)/(10^8 Hz) = 3 meters
Question 6: What happens to a wave's energy if you double its frequency?
Answer: The energy doubles. Since E = hf, doubling frequency doubles energy.
Question 7: Explain why a red object appears black under blue light.
Answer: A red object reflects only red light and absorbs other colors. Under blue light, there is no red light to reflect, so the object absorbs all the blue light and appears black.
Question 8: A wave has a period of 0.25 seconds. What is its frequency?
Answer: f = 1/T = 1/0.25 = 4 Hz
Question 9: Why do doctors use X-rays instead of visible light to see bones?
Answer: X-rays have higher frequency and energy than visible light, allowing them to penetrate soft tissue while being absorbed by dense bones, creating contrast in images.
Question 10: Write a claim about wave speed in different media and support it with evidence and reasoning.
Answer: Claim: Sound travels faster in water than in air. Evidence: Sound speed in air is ~343 m/s; in water it's ~1480 m/s. Reasoning: Water molecules are closer together than air molecules, so vibrations transfer more efficiently between particles, increasing wave speed.
Next Steps
- If you scored below 80%, review the lessons you found challenging
- Proceed to the next unit: Scientific Method
- Use the SAT/ACT skills from this unit in future practice