Question

understand: electromagnetic waves select the true statements about electromagnetic waves. choose 2 answers: a electromagnetic waves dont need a matter medium to travel through. b human eyes cannot see all electromagnetic waves directly. c all parts of the electromagnetic spectrum have the same frequency and wavelength. d some electromagnetic waves travel faster than others in a vacuum.

Explanation:

• For option A: Electromagnetic waves are transverse waves and can travel through a vacuum (no medium required), so this statement is true.
• For option B: The human eye can only detect a small portion of the electromagnetic spectrum (visible light), so it cannot see all electromagnetic waves directly, this statement is true.
• For option C: Different parts of the electromagnetic spectrum have different frequencies and wavelengths (since \( c = \lambda

u \), where \( c \) is constant in a vacuum, so \( \lambda \) and \(
u \) are inversely related), so this statement is false.

• For option D: In a vacuum, all electromagnetic waves travel at the speed of light (\( c = 3\times10^{8}\,m/s \)), so they do not travel at different speeds, this statement is false.

Answer:

A. Electromagnetic waves don't need a matter medium to travel through.
B. Human eyes cannot see all electromagnetic waves directly.