The Positrons near the Galactic Center Can Be Detected Because

question 3

Multiple Choice

The positrons near the galactic center can be detected because they annihilate with electrons and emit gamma rays. Two gamma rays are produced in such a situation to conserve both energy and momentum. Suppose the positron and electron, each with energy mc², convert all of this energy into two identical gamma-ray photons. What will be the wavelength of these photons? The mass of an electron is 9.1 * 10^-31 kg.

• A) 1.5 * 10^-2 nm
• B) 2.4 * 10^-3 nm
• C) 3.9* 10^-4 nm
• D) 7.9 *10^-5 nm

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