Circuits to Optics

1. Circuits to Optics June 16, 2004

2. Which type of field is present near a moving electric charge? (A) an electric field, only (B) a magnetic field, only (C) both an electric field and a magnetic field (D) neither an electric field nor a magnetic field

3. The electric circuit consists of a 12-volt battery, a 3.0-ohm resistor, R1, and a variable resistor, R2. At what value must the variable resistor be set to produce a current of 1.0 ampere through R1? (A) 6.0 Ω (B) 3.0 Ω (C) 9.0 Ω (D) 12 Ω

4. An electric bell connected to a battery is sealed inside a large jar. What happens as the air is removed from the jar? (A) The bell’s loudness increases because of decreased air resistance. (B) The bell’s loudness decreases because sound waves can not travel through a vacuum. (C) The electric circuit stops working because electromagnetic radiation can not travel through a vacuum. (D) The bell’s pitch decreases because the frequency of the sound waves is lower in a vacuum than in air.

5. As a sound wave passes from water, where the speed is 1.49 × 103 meters per second, into air, the wave’s speed (A) decreases and its frequency remains the same (B) increases and its frequency remains the same (C) remains the same and its frequency decreases (D) remains the same and its frequency increases

6. Which phenomenon occurs when an object absorbs wave energy that matches the object’s natural frequency? (A) reflection (B) resonance (C) diffraction (D) interference

7. Which wave diagram has both wavelength (λ) and amplitude (A) labeled correctly?

8. What is the total resistance of the circuit segment? (A) 1.0  (B) 9.0  (C) 3.0  (D) 27 

9. In the circuit diagram, what are the correct readings of voltmeters V1 and V2? (A) V1 reads 2.0 V and V2 reads 4.0 V (B) V1 reads 4.0 V and V2 reads 2.0 V (C) V1 reads 3.0 V and V2 reads 3.0 V (D) V1 reads 6.0 V and V2 reads 6.0 V

10. A 20-ohm resistor and a 30-ohm resistor are connected in parallel to a 12-volt battery as shown. An ammeter is connected as shown. What is the equivalent resistance of the circuit? (A) 10. Ω (B) 25 Ω (C) 12 Ω (D) 50. Ω

11. A 20-ohm resistor and a 30-ohm resistor are connected in parallel to a 12-volt battery as shown. An ammeter is connected as shown. What is the current reading of the ammeter? (A) 1.0 A (B) 0.40 A (C) 0.60 A (D) 0.20 A

12. A 20-ohm resistor and a 30-ohm resistor are connected in parallel to a 12-volt battery as shown. An ammeter is connected as shown. What is the power of the 30.-ohm resistor? (A) 4.8 W (B) 12 W (C) 30 W (D) 75 W

13. A physics student notices that 4.0 waves arrive at the beach every 20 seconds. The frequency of these waves is (A) 0.20 Hz (B) 16 Hz (C) 5.0 Hz (D) 80 Hz

14. An electric guitar is generating a sound of constant frequency. An increase in which sound wave characteristic would result in an increase in loudness? (A) speed (B) period (C) wavelength (D) amplitude

15. How many wavelengths separate point A and point B? (A) 1.0 (B) 3.0 (C) 1.5 (D) 0.75

16. Which diagram best represents magnetic field lines around a bar magnet?

17. The spaceship is moving away from Earth when the radio signal is received. Compared to the frequency of the signal sent from Earth, the frequency of the signal received by the spaceship is (A) lower (B) higher (C) the same

18. What is the total electrical energy used by a 1500-watt hair dryer operating for 6.0 minutes? (A) 4.2 J (B) 250 J (C) 9.0×103 J (D) 5.4×105 J

19. A periodic transverse wave has an amplitude of 0.20 meter and a wavelength of 3.0 meters. If the frequency of this wave is 12 Hz, what is its speed? (A) 0.25 m/s (C) 36 m/s (B) 12 m/s (D) 4.0 m/s

20. An electric iron operating at 120 volts draws 10 amperes of current. How much heat energy is delivered by the iron in 30 seconds? (A) 3.0 × 102 J (B) 1.2 × 103 J (C) 3.6 × 103 J (D) 3.6 × 104 J

21. A motor is used to produce 4.0 waves each second in a string. What is the frequency of the waves? (A) 0.25 Hz (B) 25 Hz (C) 15 Hz (D) 4.0 Hz

22. A surfacing whale in an aquarium produces water wave crests having an amplitude of 1.2 meters every 0.40 second. If the water wave travels at 4.5 meters per second, the wavelength of the wave is (A) 1.8 m (B) 2.4 m (C) 3.0 m (D) 11 m

23. A radar gun can determine the speed of a moving automobile by measuring the difference in frequency between emitted and reflected radar waves. This process illustrates (A) resonance (B) diffraction (C) the Doppler effect (D) refraction

24. A laser beam is directed at the surface of a smooth, calm pond. Which organisms could be illuminated by the laser light? (A) the bird and the fish (B) the crab and the seaweed (C) the bird and the seaweed (D) the crab and the fish

25. A photon of which electromagnetic radiation has the most energy? (A) ultraviolet (C) infrared (B) x ray (D) microwave

26. What is the reading on ammeter A? (A) 1.3 A (C) 3.0 A (B) 1.5 A (D) 0.75 A

27. Two pulses are traveling toward each other in a uniform medium. Which diagram best represents the medium when the pulses meet at point X? (A) (B) (C) (D)

28. A mass, M, is hung from a spring and reaches equilibrium at position B. The mass is then raised to position A and released. The mass oscillates between positions A and C. At which position, A, B, or C, is mass M located when the kinetic energy of the system is at a maximum?

29. A mass, M, is hung from a spring and reaches equilibrium at position B. The mass is then raised to position A and released. The mass oscillates between positions A and C. At which position, A, B, or C, is mass M located when the gravitational potential energy of the system is at a maximum?

30. A mass, M, is hung from a spring and reaches equilibrium at position B. The mass is then raised to position A and released. The mass oscillates between positions A and C. At which position, A, B, or C, is mass M located when the elastic potential energy of the system is at a maximum?