The focal length of a converging lens is determined through image formation, Assumin A) infinity of 100 cm and an image distance of 25 cm, what is the focal length of this lens? B) 168 mm C) 150 mm D) 91 mm E) 250 mm 2 . Let's consider light is traveling from a glass material to air, if the critical angle in this case found to be 30 in this case, what is the refractive index of the glass material? A) 2.0 B) 1.7 C) 1.6 D) 1.5 3. In an electrical heat equivalent experiment, 3000J of electrical energy is used to heat 180g of water in a calorimeter cup of mass 20g. What is the change in temperature of the water? (the specific heat the water is Cwater = Ical/g.C, the specific of cup is ccup= 0.21 cal/g'C and electrical heat equivalent EHE =4.18J/Cal) A) 12.96 .C B) 7.62 C C) 4.18 .C D) 3.90 .C 4. A RC-circuit uses a 3.6 MS resistor and a 100 uF, what is the time constant for this circuit? A) 3600 s B) 0.1375s C) 137.5 s D) 360s E) 32600s 5 The diffraction experiment used lasers to observe diffraction patterns and measure the wavelength of laser light. Suppose the distance from the central bright fringe on the screen to the first order bright fringe is found to be 4.8mm for a slit separation of 0.125 mm. The distance from slit to screen is 100cm. What is the wavelength of this laser? A) 670nm B) 515nm C) 470nm D) 600nm E) 1024nm 6. A light ray traveling in air is incident on the surface of a glass plate. The light ray makes an angle of 320 with the normal to the surface, while in the glass it makes an angle of 170. What is the refractive index of glass? (Assume the refractive index of air is 1.) A) 1.81 B) 1.1 C) 0.55 D) 1.49 E) 3.5 7. If an electrical current of 2.5A is flowing through a resistance of 100 $2 in an electrical circuit. What will be the power output from the resistance? A) 400 W B) 250W C) 350 W D) 625W. 8. An electron makes a transition from quantum level ni = 8 to level nf = 1. Based on Bohr's model for the hydrogen atom that will be the wavelength of the emitted ration? A) 92.6 nm B) 405.6 nm C) 673.2 nm D) 930.4 nm 9 If you double the frequency of the tuning fork, which of the following statements is true? A) The observed resonance positions will have a smaller value. B) The observed resonance positions will have a larger value. C) The is no change in the observed resonance positions. D) The resonance positions will only change if the temperature in the resonance tube changes. If we switch from red laser (1=670nm) to green laser (1=532nm) in a Young's double slit diffraction 10. experiment, then what happens to the fringe pattern? B) Position of the Principal maxima changed by 138 nm. A) Nothing. D) Separation between fringes decreases. C) Separation between fringes increases A coil moves in a magnetic field. Which of the following will increase induced emf? 11. a) Moving the coil fasterb) Keeping the flux constant ) Increasing the number of loops d) None of the above 12 has the following value: Based on Bohr's model for the hydrogen atom, the longest wavelength emitted for the Balmer series (ny- 2) A) ~650nm B) ~40nm C) ~700nm D) ~550nm 13. Assume the time constant for a RC circuit is 400s. The voltage on the power supply is set to 10 Volts. The equation of the best fit line to an exponential fit of the voltage vs. time data for the discharging capacitor should be: A) y = 6.0 e-0.0010x B) y = 40.0 e-10 x C) y = 6.0 e-0.0025 x D) y = 10.0 e-0.0025 x Part II: Working Problems (show all your work! Show all equations first before adding numbers. Don't forget units.) (30%) 1. Two lenses (fi=100 mm; f2=250 mm) are used to form an image of a candle on an observation screen. The distance between the lenses is kept small and is measured to be 3.5 cm. The distance of the candle from the center of the combined lenses is measured to be 105 cm and the distance of the screen from the center of the combined lenses is measured to be 9 cm. a) What is the experimental focal length of the two combined lenses (in mm)? Show the equation you use! b) What is the theoretical focal length of the two combined lenses (in mm)? Show the equation you use! . A magnet is inserted into a coil of wire consisting of 100 loops. The cross-sectional area of the coil is 5x102 m. Before inserting the magnet (initial time: to=0 s) the magnetic field at the location of the coil is Bo=4T. After inserting the magnet (later time: t=60 s) into the coil the magnetic field has increased in the coil to B=10 T. Assume that the angle 0 between surface normal of the coil and magnetic field is 450 at all times. Using Faraday's Law, determine the average induced voltage (emf) induced in the coil