Question

Which one of the following correctly represents the change in wave characteristics (all in vacuum) from microwaves to X-rays in electromagnetic spectrum?

• A. Speed remains same, Wavelength decreases, Frequency remains same
• B. Speed remains same, Wavelength decreases, Frequency increases
• C. Speed increases, Wavelength increases, Frequency decreases
• D. Speed remains same, Wavelength increases, Frequency remains same

Hint:

In the electromagnetic spectrum, the speed of light is constant in a vacuum, but the wavelength and frequency are inversely related. As wavelength decreases, frequency increases.

Answer 1

The Correct Option is B

To characterize the transition from microwaves to X-rays within the electromagnetic spectrum, it is essential to review fundamental electromagnetic wave properties:

• Speed: The speed of electromagnetic waves in a vacuum is constant and equal to c = 3 × 10⁸ m/s. This speed remains the same throughout the entire electromagnetic spectrum.
• Wavelength and Frequency: The relationship between speed (c), frequency (f), and wavelength (λ) is given by the equation c = λf. Since the speed is constant, a decrease in wavelength must be accompanied by an increase in frequency.

Observing the progression from microwaves to X-rays:

• Wavelength: Decreases. Microwaves have much longer wavelengths compared to X-rays.
• Frequency: Increases. As wavelength decreases, frequency increases to maintain constant speed, as required by the relation c = λf.

Conclusion:
From microwaves to X-rays, the speed of electromagnetic waves remains constant, the wavelength decreases, and the frequency increases.