The current definition of the standard kilogram of mass is based on
A) the mass of the earth.
B) the mass of the sun.
C) the mass a particular object kept in France.
D) the mass of a cesium-133 atom.
Question 2
Two in-phase loudspeakers are some distance apart. They emit sound with a frequency of 572 Hz. A microphone is moved between the speakers to record the wave amplitude at points along that line.
What is the spacing between points where constructive interference occurs? The speed of sound in air is 343 m/s. A) 0.300 m
B) 0.600 m
C) 0.900 m
D) 1.20 m
E) 1.50 m