The Electromagnetic Spectrum

Electromagnetic radiation is present everywhere, even in space, as it doesn't need a medium to travel. It consists of electric and magnetic fields created by electron movement, forming transverse waves. The electromagnetic spectrum ranges from tiny wavelengths to kilometers, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. These waves can be described by wavelength or frequency. Natural sources like stars and man-made sources emit this radiation, which is useful due to its energy. As wavelength decreases, frequency and energy increase, leading to ionisation, where high-frequency waves can free electrons, creating charged ions. Electromagnetic radiation is essential for life.

What is the nature of electromagnetic waves in terms of their oscillation?

• They oscillate at right angles to each other and the direction of travel.

• They oscillate parallel to the direction of travel.

• They oscillate in a circular motion.

• They do not oscillate.

Which of the following is NOT a type of electromagnetic wave?

• Sound waves

• Radio waves

• X-rays

• Ultraviolet rays

What determines the usefulness of electromagnetic radiation?

• Its speed

• Its energy

• Its color

• Its size

What happens to the frequency and energy of electromagnetic waves as the wavelength decreases?

• Frequency decreases and energy decreases

• Frequency decreases and energy increases

• Frequency increases and energy increases

• Frequency increases and energy decreases

What is the process called when high-frequency waves free electrons from atoms?

• Radiation

• Ionization

• Conduction

• Reflection