Waves and Electromagnetic Spectrum Flashcards
Grade 7 · Science · Flashcards
Key terms and concepts for understanding how waves transfer energy and how electromagnetic radiation is organized.
Flashcards
- Wave
- A disturbance that transfers energy through matter or space without transferring matter itself.
- Wavelength
- The distance between two consecutive identical points on a wave (e.g., crest to crest), measured in meters or nanometers.
- Frequency
- The number of complete wave cycles passing a point per second; measured in hertz (Hz).
- Amplitude
- The maximum distance a wave moves from its resting position; determines how much energy the wave carries.
- Transverse wave
- A wave where the medium moves perpendicular to the direction the wave travels; light and water waves are examples.
- Longitudinal wave
- A wave where the medium moves parallel to the direction the wave travels; sound is an example.
- Electromagnetic spectrum
- The full range of electromagnetic radiation arranged from longest wavelength (radio waves) to shortest (gamma rays).
- Radio waves
- Electromagnetic waves with the longest wavelengths and lowest energy; used in communication technologies.
- Infrared radiation
- EM radiation just beyond red light; experienced as heat, used in thermal imaging and remote controls.
- Ultraviolet (UV) radiation
- EM radiation just beyond violet light; higher energy than visible light; causes sunburn and is largely blocked by Earth's ozone layer.
- X-rays
- High-energy electromagnetic waves that can penetrate soft tissue but are absorbed by bone; used in medical imaging.
- Gamma rays
- The most energetic electromagnetic waves with the shortest wavelengths; emitted by radioactive decay.
- Speed of light
- All electromagnetic waves travel at approximately 3 × 10⁸ m/s in a vacuum; the fastest known speed.
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