NY Regents January 2008, Part 2
21. An electric circuit contains a variable resistor connected to a source of constant potential difference. Which graph best represents the relationship between current and resistance in this circuit?
22 In the circuit diagram below, two 4.0-ohm resistors are connected to a 16-volt battery as shown.

The rate at which electrical energy is expended in this circuit is
23. Increasing the amplitude of a sound wave produces a sound with
24. The product of a wave’s frequency and its period is
25. A periodic wave having a frequency of 5.0 hertz and a speed of 10. meters per second has a wavelength of
26. An electromagnetic wave traveling through a vacuum has a wavelength of 1.5 × 10–1 meter. What is the period of this electromagnetic wave?
27. A ray of light (f = 5.09 × 1014 Hz) traveling in air strikes a block of sodium chloride at an angle of incidence of 30.°. What is the angle of refraction for the light ray in the sodium chloride?
28 The speed of a ray of light traveling through a substance having an absolute index of refraction of 1.1 is
29. Resonance occurs when one vibrating object transfers energy to a second object causing it to vibrate. The energy transfer is most efficient when, compared to the first object, the second object has the same natural
30. A subatomic particle could have a charge of
31. Two pulses traveling in the same uniform medium approach each other, as shown in the diagram below.

Which diagram best represents the superposition of the two pulses?
32. A police car traveling at a speed of 30.0 meters per second sounds its siren, which has a frequency of 1.00 × 103 hertz. As the police car approaches a stationary pedestrian, the pedestrian detects a siren frequency of
33. A variable-frequency light source emits a series of photons. As the frequency of the photon increases, what happens to the energy and wavelength of the photon?

34. Which diagram best represents the shape and direction of a series of wave fronts after they have passed through a small opening in a barrier?
35. The diagram below represents the sequence of events (steps 1 through 10) resulting in the production of a D meson and a D+ meson. An electron and a positron  (antielectron) collide (step 1), annihilate each other (step 2), and become energy (step 3). This energy produces an anticharm quark and a charm quark (step 4), which then split apart (steps 5 through 7). As they split, a down quark and an antidown quark are formed, leading to the final production of a D– meson and a D+ meson (steps 8 through 10).

Which statement best describes the changes that occur in this sequence of events?

36. A joule is equivalent to a
37. The weight of a chicken egg is most nearly equal  to
38. Two forces act concurrently on an object. Their resultant force has the largest magnitude when the angle between the forces is
39. A bicycle and its rider have a combined mass of 80. kilograms and a speed of 6.0 meters per second. What is the magnitude of the average force needed to bring the bicycle and its rider to a stop in 4.0 seconds?
40. Gravitational forces differ from electrostatic forces in that gravitational forces are