12. When a radio telescope observes a region of space between two stars, it detects electromagnetic radiation that has a wavelength of 0.21 m. This radiation was emitted by hydrogen atoms in the gas and dust located in that region. What is the frequency of this radiation? A) 7.1 × 1010 Hz B) 2.1 × 1014 Hz C) 3.0 x 108 Hz D) 6.9 x 101 Hz E) 1.4 × 10° Hz Ans: E

12. When a radio telescope observes a region of space between two stars, it detects electromagnetic radiation that has a wavelength of 0.21 m. This radiation was emitted by hydrogen atoms in the gas and dust located in that region. What is the frequency of this radiation? A) 7.1 × 1010 Hz B) 2.1 × 1014 Hz C) 3.0 x 108 Hz D) 6.9 x 101 Hz E) 1.4 × 10° Hz Ans: E