Question

read the statements given below. if the statement is true, write t on the line in front of the statement. if it is false, write f and rewrite the statement to make it true. 13) _ radiant energy spreads out from its source in all directions. 14) _ electromagnetic radiation includes only visible light waves. 15) _ microwaves are a type of infrared wave. 16) _ x rays have more energy than gamma rays. 17) _ radio waves, microwaves and ultraviolet waves all have longer wavelengths than visible light. 18) _ both x rays and gamma rays have higher frequencies than ultraviolet rays. 19) _ the sun radiates both visible energy and invisible energy. 20) _ communicating with satellites is an application of gamma rays.

Explanation:

• 13: Radiant energy is energy carried by electromagnetic waves. Electromagnetic waves spread out from their source in all directions. So this statement is true.
• 14: Electromagnetic radiation includes a wide range of waves such as radio waves, microwaves, infrared, visible light, ultraviolet, X - rays, and gamma rays. So the original statement is false.
• 15: Microwaves and infrared waves are different types of electromagnetic waves. Microwaves have longer wavelengths than infrared waves. So the original statement is false.
• 16: Gamma rays have more energy than X - rays. This is because energy of electromagnetic waves is related to frequency (\(E = h

u\), where \(h\) is Planck's constant and \(
u\) is frequency), and gamma rays have higher frequencies than X - rays. So the original statement is false.

• 17: Radio waves and microwaves have longer wavelengths than visible light, but ultraviolet waves have shorter wavelengths than visible light. So the original statement is false.
• 18: X - rays and gamma rays have higher frequencies than ultraviolet rays. Since frequency and energy are related (\(E = h

u\)), and X - rays and gamma rays are more energetic than ultraviolet rays. So this statement is true.

• 19: The Sun radiates a broad spectrum of electromagnetic radiation. It radiates visible light (which we can see) and also invisible radiation like infrared, ultraviolet, X - rays etc. So this statement is true.
• 20: Communicating with satellites is mainly an application of radio waves (which are a type of electromagnetic wave with long wavelengths). Gamma rays are highly energetic and not used for satellite communication. So the original statement is false.

Answer:

1. T
2. F. Electromagnetic radiation includes radio waves, microwaves, infrared, visible light, ultraviolet, X - rays, and gamma rays.
3. F. Microwaves are a type of electromagnetic wave different from infrared waves.
4. F. Gamma rays have more energy than X rays.
5. F. Radio waves and microwaves have longer wavelengths than visible light, but ultraviolet waves have shorter wavelengths than visible light.
6. T
7. T
8. F. Communicating with satellites is an application of radio waves.