7. An electron is accelerated through a potential difference of 12.1 V. n = 5 -0.54 eV 0.8 eV n = 3 -1.5 eV n = 2 -3.4 eV n = 1 -13.6 eV (a) How much kinetic energy has it gained in (i) electronvolts (ii) joules? (b) This electron hits a hydrogen atom and excites it. (i) Explain what is meant by excitation (ii) Using the energy values given in the diagram above, work out the two energy levels between which this accelerated electron will likely produce a transition. (iii) Calculate the energies of the three photons that might be emitted as the electron return to the ground state.

Here's how gym membership works for a potential customer: If the customer decides to join the gym, she will pay J on day 0. Then, she can use the gym starting the next day for 5 days (1; 2; 3; 4; 5), paying an additional F on each day she visits. If she goes to the gym on any given day, it costs her (10+ F) that day, but beneÖts her 30 the next day. In other words, her "costs" are a sum of her psychic costs (10) and actual Onancial costs (F). Assume that, when indi§erent, the individual will go to the gym. (a) Suppose the potential customer is a standard exponential discounter with a discount factor of = 12. If gym membership was free (i.e. J = 0 and F = 0) would she join the gym? If so, how many days would she actually go? (b) Suppose the gym did not charge a joining fee. How high could it set the usage fee? What would its revenues from this customer be? (c) Suppose instead the gym decided not to charge a usage fee. How high could it set the joining fee? [Hint: To Ögure out the…

Consider the vectors A=<1,2,3>, B=<-2,1,0>, and C=<0,3,1>. (a)Find the angle between A and B. (b)Find the component of A in the direction of C.

(6%) Problem 5: Consider the following vectors: A = 4.6i + 1.4j+ 3.4k В = -6. 5i + 7.1j + 10.2k 25% Part (a) What is the x-component of the vector V = 3(A × 2B)? Vx= sin() cos() tan() 7 8 9 НOME cotan() asin() acos() E 4 5 atan() acotan() sinh() 1 cosh() tanh() cotanh() + END Degrees Radians Vd BACKSPACE DEL CLEAR Feedback Submit Hint I I give up! Hints: 2 for a 0% deduction. Hints remaining: 0 Feedback: 3% deduction per feedback. -This is a cross-product, so the answer will be a vector. In this part, we just want the x-component of the vector. Keep in mind that scalars like "2" and "3" distribute 3.

Given the vectors A=7-6ŷ+9 2 B=-5-2ŷ Is the angle sandwiched between them acute or obtuse?