Q 19.1: A particle called the pion lives on the average only about 2.6 * 10(-8)s when at rest in the laboratory. It then changes to another form. How long would such a particle live when shooting through the space at 0.95c?

Q 19.2: What is the mass of a 70kg man in a space rocket traveling at 0.8c from us as measured from Earth?

Q 19.3: Find the energy of photon in (a) Radiowave of wavelength 100m (b) Green light of wavelength 550nm (c) X-ray with wavelength 0.2nm.

Q 19.4: Yellow light 577nm wavelength is incident on a cesium surface. The stopping voltage is found to be 0.25 V. Find (a) the maximum K.E. of the photoelectrons (b) the work function of cesium.

Q 19.5: X-rays of wavelength 22pm are scattered from a carbon target. The scattered radiation being viewed at 85 degree to the incident beam. What is Compton shift?

Q 19.6: A 90 KeV X-ray photon is fired at a carbon target and Compton scattering occurs. Find the wavelength of the incident photon and the wavelength of the scattered photon for scattering angle of (a) 30 (b) 60.

Q 19.7: What is the maximum wavelength of the two photons produced when a positron annihilates an electron? The rest mass energy of each is 0.51 MeV.

Q 19.8: Calculate the wavelength of (a) a 140 g ball moving at 40 m/s (b) a proton moving at the same speed (c) an electron moving at the same speed.

Q 19.9: What is the de Broglie wavelength of an electron whose kinetic energy is 120 eV?

Q 19.10: An electron is placed in a box about the size of an atom that is about 1 * 10(-10)m. What is the velocity of the electron?