1. A rocket speeds past an asteroid at 0.800 c. If an observer in the rocket sees 10.0 s pass on her watch, how long would that time interval be as seen by an observer on the asteroid? 2. An electron has a rest mass of 9.11 x 10781 kg. In a detector, it behaves as if it has a mass of 12.55 x 10 3kg. How fast is that electron moving relative to the detector? Communication 1. If the mass loss during a nuclear reaction is 14 micro grams. How much energy is realised? 12. Calculate the maximum KE and velocity of an electron ejected from zinc by a 275mm photon. Table 12.1 Work Functions of Some Common Metals Work function Metal (eVI aluminum 4.28 calcium 2.87 cesium 2.14 4.65 iron 4.50 land 4.25 lithium 2.90 nickel 5.15 platinum 5.65 potassium 2.30 Lin 1.42 tungsten 4.55 zinc 4.33 Thinking 1. How many photons are emitted per second by a 5mW laser source operating at 632.8nm. NJ2. A hydrogen atom moving at a speed v absorbs a photon of wavelength 122nm and stops. Find the value of v if the mass of hydrogen is 1.67 x 10-27 kg Application 1. What is the wavelength of the radiation emitted when the electron in a hydrogen atom jumps from n=co to n = 2 2. Ultraviolet light of wavelength 280mm is used in an experiment on photoelectric effect with lithium (work function = 2.5ev). Find the KE of the photo electrons 3