in an experiment, a ringing bell is placed in a vacuum jar that does not have any air in it. what  best  describes why the bell is seen vibrating but not heard? light waves have high frequencies and are able to pass through the vacuum jar, but the frequencies of sound waves are too low to vibrate a vacuum. light waves travel faster than sound waves, so they are able to travel through the vacuum jar, but sound waves do not have enough energy to vibrate glass. light does not need a medium to travel through, but since sound waves must have a medium to vibrate, sound is not created where no air is present. light is a longitudinal wave that is able to pass through the vacuum jar, but sound is a transverse wave that has to move perpendicular to air.

Heena wants to measure the volume of a ball that is 24 cm across. how should she set up her equation?

Jessie ran 5000 meters from the cops and an average speed of 6 meters / second before he got caught . how long did he run?

The particle in a two-dimensional well is a useful model for the motion of electrons around the indole ring (3), the conjugated cycle found in the side chain of tryptophan. we may regard indole as a rectangle with sides of length 280 pm and 450 pm, with 10 electrons in the conjugated p system. as in case study 9.1, we assume that in the ground state of the molecule each quantized level is occupied by two electrons. (a) calculate the energy of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels. 9.27 electrons around the porphine ring (4), the conjugated macrocycle that forms the structural basis of the heme group and the chlorophylls. we may treat the group as a circular ring of radius 440 pm, with 20 electrons in the conjugated system moving along the perimeter of the ring. as in exercise 9.26, assume that in the ground state of the molecule quantized each level is occupied by two electrons. (a) calculate the energy and angular momentum of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels.