A sound wave radiates from a source in all directions. If the power of the sound source is 200 watts, then the intensity level of the sound wave 1000 m from the source is (in dB)
A. 62.8.
B. 66.0.
C. 68.5.
D. 70.5.
E. 72.0.
E. 72.0.
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Two different isotopes of the same element have
A) the same chemical properties, and also the same properties in nuclear processes. B) different chemical properties, but the same properties in nuclear processes. C) different chemical properties, and also different properties in nuclear processes. D) the same chemical properties, but different properties in nuclear processes. E) None of the above.
The weak force that acts between an electron and a quark is caused by the exchange of
a. photons. b. gluons. c. gravitons. d. W+, W–, or Z0 bosons.
As an object moves from point A to point B only two forces act on it: one force is nonconservative and does -30 J of work, the other force is conservative and does +50 J of work. Between A and B,
a. the kinetic energy of object increases, mechanical energy decreases. b. the kinetic energy of object decreases, mechanical energy decreases. c. the kinetic energy of object decreases, mechanical energy increases. d. the kinetic energy of object increases, mechanical energy increases. e. None of the above.
When a photon collides with a free electron at rest and the direction of motion of the photon changes,
a. the magnitude of the momentum of the photon does not change. b. the momentum of the electron does not change. c. the kinetic energy of the electron does not change. d. the total energy of the photon does not change. e. both the magnitude of the momentum and the total energy of the photon decrease.