Correct:
- Radio telescopes give us information about the birthplace of a star
- Visible light is a kind of electromagnetic wave
- All objects emit electromagnetic waves
Incorrect:
- All waves have the same wavelength
- If the wavelength of a wave increases, its frequency also increases
Explanation:
Let's analyze each sentence.
- Radio telescopes give us information about the birthplace of a star --> TRUE. In fact, radio telescopes analyze radio waves, which are electromagnetic waves that can travel from distant places (such as stars) to us without being absorbed by gas and interstellar dust along the path.
- All waves have the same wavelength --> FALSE. For instance, radio waves have longer wavelength than visible light, or gamma rays have shorter wavelength than infrared radiation.
- Visible light is a kind of electromagnetic wave --> TRUE. Visible light corresponds to a portion of the electromagnetic spectrum, that goes from wavelength of 350 nm to wavelength of 700 nm (approximately), and it contains all the colors of visible ligth.
- If the wavelength of a wave increases, its frequency also increases --> FALSE. It's actually the opposite: as the wavelength increases, the frequency decreases, according to the equation
[tex]\lambda = \frac{c}{f}[/tex]
where c is the speed of light and f is the frequency.
- All objects emit electromagnetic waves --> TRUE. Every object emits ome electromagnetic waves, and the peak wavelength of their emission depends on the temperature of the object.
