Electrons got ejected out as if they were ping pong balls by the light particle (photon).  Electrons were not moving initially. Then, it was moving later because of the light. a. What is the momentum of the electron initially (p=mv) Hint: Is it moving initially? b.  Does the electron have momentum after being hit by the light particle? Hint: Is it moving after being hit? c.    What can you infer about light particles and momentum? Hint: Where is the electron getting its velocity from

For part c), how come we cannot use the relativistic momentum equation where p = mv/(sqrt(1-v^2/c^2))? Since we've already solved for velocity in part b)?

1. axextes A particle interacts with other particles in a uniform density medium and executes a random walk. If the particle takes an average time t to travel a distance L away from its starting point, about how long on average does the particle take to travel a distance 2L away from its starting point? A. 0.5t B. t C. 1.4 t D. 2 t E. 4t

A Carbon-14 nucleus is initially at rest but emits two particles of radiation; one with momentum 5.8x10-21kgm/s[E], and another with momentum 4.5x10-21kgm/s[S]. If the residual Carbon-14 mass is 2.3x10-26kg; a. Determine the residual Carbon 14 momentum magnitude b. Determine the residual Carbon 14 momentum direction c. determine the residual Carbon 14 velocity.

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Determine the speed of an electron that has a kinetic energy of 5 eV.   a. 1.33 x 106 m/s b.3.00 x 108 m/s  c.2.66 x 106 m/s  d.5.00 m/s

2. Astronaut A is moving away from Astronaut Bat half the speed of light. Astronaut A turns on and off a laser so that the beam is on for 1.00s as measured by Astronaut A. a. How fast is the light moving in the reference frame of Astronaut B? b. How much time is the beam on as measured by Astronaut B? c. The laser emits a wavelength of 635nm as seen in the reference frame of Astronaut A. What wavelength is observed in the reference frame of Astronaut B?

Stopping potential (V) 7.0 6.0 5.0 4.0 3.0 2.0 1.0 f(10¹5 Hz) 0 0.50 1.0 1.5 2.0 2.5 3.0 Fig. 1 The graph in Fig. 2 shows the stopping potential as a function of the frequency of the incident light falling on a metal surface. Find the work function of this metal. A. 5.169 eV. B. 3.422 eV. C. 1.089 eV. D. 0.773 eV.

2. An alternative derivation of the mass-energy formula E, = moc² also given by Einstein, is based on the principle that the location of the center of mass (CM) of an isolated system cannot be changed by any process that occurs inside the system. The Figure below shows a rigid box of length L that rests on a frictionless surface; the mass M of the box is equally divided between its two ends. A burst of electromagnetic radiation of energy E, is emitted by one end of the box. According to classical physics, the radiation has the momentum p = "0%c , and when it is emitted, the box recoils with the speed v z Eo/ so that the total momentum of Mc the system remains zero. After a time t z L/c the radiation reaches the other end of the box and is absorbed there, which brings the box to a stop after having moved the distance S. If the CM of the box is to remain in its original place, the radiation must have transferred mass from one end to the other. Show that this amount of mass is m, = c2.

4. Consider following the following the fusion nuclear reaction: n+p+p→;He. What happens to the different types of potential energies of this system as a result the reaction (i.e. the electrical potential energy and the strong nuclear potential energy)? The atomic mass of He is 3.016029 u. a. The electrical potential energy and the strong nuclear potential energy both increase. b. The electrical potential energy increases and the strong nuclear potential energy decreases. c. The electrical potential energy increases and the strong nuclear potential energy remains the same. d. The electrical potential energy decreases and the strong nuclear potential energy increases. e. The electrical potential energy and the strong nuclear potential energy both decrease.