1PE: Concepts of Wavelength and Frequency Two electromagnetic waves are represented in the margin, (a) Which wave has the higher frequency? (b) If one wave represents visible light and the other represents infrared radiation, which wave is which? A source of electromagnetic radiation produces infrared light. Which of the following could be the wavelength of the light? (a) 3.0 nm (b) 4.7 cm (c) 66.8 m (d) 34.5 pm (e) 16.5 A
Solution: Here, we are going to identify which of the given wavelength is the wavelength of light. Step1: Electromagnetic radiations are the waves having both electric and magnetic fields associated with them. The arrangement of different types of electromagnetic radiations in the order of increasing wavelengths is called electromagnetic spectrum. The complete electromagnetic spectrum is given below: Step2: Now, a) 3.0 nm = 3 x 10 m, lies in the x-ray region. [1 nm = 10 m] -9 b) 4.7 cm = 4.7 x 10 m, lies in the microwave region. [1 cm = 10 m] -2 c) 66.8 m = 6.68 x 10 m, lies in the radio waves region. d) 34.5 m = 3.45 x 10 m, lies in the infrared region. [1 m = 10 m] -6 e) 16.5 A = 1.65 x 10 m, lies in the x-ray region. [1 A = 10 -10m] Thus, the correct option is (d). ---------------
