Fluids density Pascal s principle (pressure vs. depth) Equation of continuity Buoyant force Bernoulli s (pressure, velocity, depth)

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1 Final Exam All Finals week in the testing center. 50 multiple choice questions. Equations on the back of the test. Calculators are allowed on the test. There is a practice test in the packet.

2 Exam 1 Review Fluids density Pascal s principle (pressure vs. depth) Equation of continuity Buoyant force Bernoulli s (pressure, velocity, depth)

3 A block of wood floats in a bowl of water. On top of the block there is a lead weight attached. The block turns over so that the lead weight is under water still attached to the floating block. When this happens, the water level in the bowl (a) goes down. (b) remains unchanged. (c) goes up.

4 A block of wood is glued to the bottom of a container. Water in the container completely covers the block. The glue dissolves and the block rises to the top where it floats. When this happens, the water level (a) goes up. (b) remains unchanged. (c) goes down.

5 A cannon is placed in a boat. The boat sinks a little to displace more water. The amount of new water displaced is 1. A volume of water that weighs more than the cannon. 2. A volume of water that weighs as much as the cannon. 3. A volume of water that weighs less than the cannon.

6 If the cannon now falls from the boat into the water and sits on the bottom of the lake the amount of water displaced by the cannon is 1. A volume of water that weighs more than the cannon. 2. A volume of water that weighs as much as the cannon. 3. A volume of water that weighs less than the cannon.

7 Discussion question: A glass is filled to the top with ice and water. When the ice melts, where is the water level? 1. Above the rim so it spills over. 2. At the rim same place as before. 3. Below the rim

8 Blood flows through a coronary artery that is partially blocked by deposits along the artery wall. Through which part of the artery is the flow speed largest? 1. The narrow part. 2. The wide part. 3. The speed is the same in both parts.

9 A tornado moves over a house and causes the windows to explode. They will explode (a) outward. (b) inward.

10 Sound Waves Transverse vs. longitudinal waves Frequency, period, wavelength Antinodes, nodes Doppler effect Pipes and strings Resonances

11 A sinusoidal wave propagates on a string. The tension in a string remains fixed, but the frequency is doubled. What happens to the wavelength? (a) The wavelength is halved. (b) The wavelength remains unchanged. (c) The wavelength is doubled.

12 A flute is played with helium inside instead of air. The wavelength (inside the flute) of the fundamental note (a) decreases. (b) remains unchanged. (c) increases.

13 Two strings, one thick and the other thin, are connected to form one long string. A wave travels along the string and passes the point where the two strings are connected. Which of the following does not changes at that point: 1. frequency 2. velocity 3. wavelength

14 You hear a violinist playing a series of notes of decreasing wavelength. As the wavelength decreases, the wave speed in the string 1. Decreases 2. Increases 3. Stays the same

15 A string fastened at both ends has a length of 1.0 m. Two possible wavelengths for standing waves are 1. 4 m and 2 m 2. 4 m and.5 m 3. 2 m and.66 m 4. 3 m and.66 m 5. 3 m and 2 m 6. 3 m and.5 m 7. 2 m and.20 m

16 Two tuning forks have frequencies 440Hz and 438Hz. When they are both struck, a listener hears the intensity vary in time (i.e. wa - wa - wa -...). What is the period of this intensity variation?

17 A stationary observer hears a pitch from a source that moves towards him, the observed frequency will be the source frequency 1. Lower than 2. The same as 3. Higher than

18 Test 2 Review Ideal Gas PV=nRT Watch units W=P V; work done by gas vs. on gas Adiabatic, constant V, T and P Thermal equilibrium Entropy Heat --Internal energy kinetic vs. T 1st and 2nd laws of thermodynamics U = Q + W Heat transfer: Q=mc T Phase change: Q=mL Radiation, convection, conduction

19 A room is measured with a steel measuring tape at 20 o C and found to measure exactly 10 feet wide. The same room is measured again on a day when the temperature is 27 o C. 1. Greater than 10 feet 2. Less than 10 feet. 3. Exactly 10 feet. The original question asked: Assuming that the room does not change size, the measurement will be Why does this problem state this assumption? If α steel =11 x 10-6 / o C and α concrete =12 x 10-6 / o C

20 You heat a disc with a hole in it. Will the hole expand or shrink, or stay the same? 1. Expand 2. Shrink 3. Stay the same Demo: Heat ring does ball still fit?

21 In an ideal gas, if you double the volume of the container, while keeping the temperature and the number of molecules the same, the pressure in the gas 1. Decreases 2. Stays the same 3. Increases

22 Suppose we have two jars of gas, one of helium and one of oxygen. If both jars have the same volume, and the two gases are at the same pressure and temperature, which jar contains the greatest number of molecules? 1. Jar of helium 2. Jar of oxygen 3. Both jars contain the same number. Consider both gases to obey the ideal gas law. Also note that the mass of an oxygen atom is greater than the mass of a helium atom.

23 C water =4186 J/kg o C C gold =129 J/kg o C Which heats up faster using the same heat source? 1. 1 kg water 2. 1 kg gold 3. They both heat up at the same rate. Q mc T Q is energy transferred

24 Put 100g Al at 100 o C into 500g water at 20 o C. What is the final T? c Al =900 J/kg o C c H2O =4186 J/kg o C What will the final T be? o o o o o

25 The first law of thermodynamics E int = Q + W Change of internal energy = heat put into system + work done on system The internal energy of an ideal gas depends only on the temperature of the gas.

26 True or False: Given two different objects, the one with the higher temperature contains more heat. (a) T (b) F

27 The path shown below is adiabatic (Q = 0). The change in internal energy of the gas is P V 1. Positive 2. Negative 3. zero

28 In the path shown, the change in internal energy of the gas is P 1. Negative 2. Positive 3. Zero V

29 In the path shown below, the gas returns to its original state. The net change in internal energy is P V 1. Positive 2. negative 3. zero

30 In the path shown below, the heat Q put into the gas is (a) negative. (b) zero. (c) positive. P V

31 In the path shown below, the gas returns to its original state. The heat put into the gas is P V 1. Positive 2. negative 3. zero

32 One of the P-V curves below is for an isothermal process. The other is for an adiabatic process. Which is adiabatic? P B A V

33 Two gases in separate containers have equal volumes, equal numbers of molecules, and the same internal energy E int. However, one gas is monatomic and the other is diatomic. The pressure of the diatomic gas is 1. Less than that of the monatomic gas. 2. The same of that of the monatomic gas. 3. Greater than that of the monatomic gas.

34 The second law of thermodynamics says for a heat engine 1. You can t get more work energy out than you consume in heat 2. You can t get out all of the heat energy as work 3. You will get out more work energy than you consume in heat

35 Test 3 Review Reflection Refraction-Snell s Law Mirrors-equations and drawing principle rays Lenses-equations and drawing principle rays Real and virtual images Camera, Glasses, telescope, microscope, Double and Single slit interference Thin film interference Resolution

36 An object is placed in front of a concave mirror. Depending on the position of the object, the image formed may occur 1. Behind the mirror and be real 2. In front of the mirror and be virtual. 3. In front of the mirror and be upright 4. None of the above

37 Which of the following best describes the image for a thin diverging lens that forms whenever the magnitude of the object distance is less than that of the lens' focal length? 1. Real and upright 2. Real and inverted 3. Virtual and upright 4. Virtual and inverted

38 You are designing eyeglasses for someone whose near point is 60 cm. What focal length lens should you prescribe so that an object can be clearly seen when placed at 25 cm in front of the eye? cm cm cm cm cm

39 Group question: a flat glass microscope slide (n=1.5) in air is illuminated with green light (λ=520 nm). Light reflects off both surfaces. What do you see in top view (what is the combined light reflected off the slide)? 1. All black 2. All bright 3. Dark and bright fringes similar to the two slit interference pattern 4. Not enough information We must know how far the second ray travels in the glass to know if it is in-phase with the first ray or not. If the thickness of the glass is such that the second rays ends up in-phase with the first then we see a bright green. If the two rays are out of phase then the slide will look black the two rays cancel.

40 Discussion question: An oil film on water reflects different colors more or less brightly owing to interference, depending on the film thickness. All the colors reflect brightly where the film is thinnest. (thin compared to visible wavelengths, approximately zero but enough to have a reflected ray off the oil and the water), From this information, we can tell that the index of refraction of the oil is 1. Less than that of water. 2. The same as that of water. 3. Greater than that of water.

41 Discussion question: An interference pattern is formed on a screen by shining a planar wave on a double-slit arrangement (left). If we cover one slit with a glass plate (right), the phases of the two emerging waves will be different because the wavelength is shorter in glass than in air. If the phase difference is 180, how is the interference pattern, shown left, altered? 1. The pattern vanishes 2. The bright spots lie closer together. 3. The bright spots are farther apart. 4. There are no changes. 5. Bright and dark spots are interchanged