5.2 Flashcards
Q: How are electromagnetic waves defined?
A: Electromagnetic waves are defined as transverse waves that transfer energy from the source of the waves to an absorber.
Q: What are the shared properties of all electromagnetic waves?
A: All electromagnetic waves share the following properties:
They are all transverse waves.
They can all travel through a vacuum.
They all travel at the same speed in a vacuum.
Q: How do electromagnetic waves transfer energy?
A: Electromagnetic waves transfer energy from one point to another, such as from a source to an absorber. Waves with shorter wavelengths carry higher energy, making them more dangerous. For example, ultraviolet, X-rays, and gamma rays have higher energy and can cause harm to living organisms.
Q: How do microwave ovens transfer energy to heat food?
A: Microwave ovens transfer energy from the electronics to heat the food inside by using microwave radiation. Water molecules in the food absorb certain wavelengths of microwave radiation, causing them to vibrate and generate heat, thus heating the food.
Q: What is the role of infrared radiation in energy transfer?
A: Infrared radiation is emitted by all hot objects and can be absorbed by other objects, thereby warming them up. This mechanism is commonly used in devices like heaters and infrared lamps.
Q: How does the Sun transfer energy to Earth?
A: The Sun emits several types of electromagnetic radiation, including visible light, infrared waves, and ultraviolet waves. Visible light allows living creatures to see, infrared waves heat up the Earth, and ultraviolet waves provide plants with the energy needed for photosynthesis.
Q: What is the relationship between frequency and wavelength in the electromagnetic spectrum?
A: The relationship is that the higher the frequency, the shorter the wavelength, and conversely, the lower the frequency, the longer the wavelength.
Q: How does the equation v = fλ explain the relationship between frequency and wavelength?
A: The equation v = fλ represents the speed of a wave (v) equal to the product of its frequency (f) and wavelength (λ). Since all electromagnetic waves travel at the speed of light (c), which is constant, if the frequency (f) increases, the wavelength (λ) must decrease, and vice versa.
Q: What is the significance of the relationship between frequency and energy in electromagnetic radiation?
A: The higher the frequency of electromagnetic radiation, the higher its energy. Radiation with higher energy is highly ionizing and can be harmful to cells and tissues, potentially causing cancer. Examples include UV, X-rays, and gamma rays. Conversely, radiation with lower energy is less harmful and is often used for communication purposes.
Q: How is the electromagnetic spectrum organized?
Q: How is the electromagnetic spectrum organized?
A: The electromagnetic spectrum is organized into several main groupings based on wavelengths or frequencies, including radio waves, microwaves, infrared, visible light (which encompasses colors from red to violet), ultraviolet, X-rays, and gamma rays. These groupings are arranged from longest wavelength (lowest frequency) to shortest wavelength (highest frequency).
Q: What is visible light, and how does it compare to the entire electromagnetic spectrum?
A: Visible light is the range of wavelengths that are visible to humans. It comprises only a small portion (0.0035%) of the entire electromagnetic spectrum. Visible light is characterized by different colors, with red having the longest wavelength and violet having the shortest. It is the only part of the spectrum detectable by the human eye, but certain animals can perceive beyond visible light, such as into the infrared and ultraviolet wavelengths.
Q: What are the applications of radio waves?
A: Radio waves are used in communication systems such as AM and FM radio broadcasting, television broadcasting, radar systems for navigation and weather forecasting, and wireless communication technologies like Wi-Fi and Bluetooth.
Q: How are microwaves utilized in everyday life?
A: Microwaves are commonly used in microwave ovens for cooking food quickly and efficiently. They are also used in telecommunications, particularly in satellite communication, and in radar systems for tracking and navigation.
Q: What are the practical applications of infrared radiation?
A: Infrared radiation is used in thermal imaging cameras for night vision, remote controls for electronics, temperature measurement devices such as infrared thermometers, and in infrared heating systems.
Q: What is the main application of visible light?
A: Visible light is essential for human vision and is used in various lighting applications, photography, and optical communication systems such as fiber optics.
