745.92 hz (b)
this is hte answer only because i seen it on the question lol
The velocity of sound in at 300C is 511.3 m/s.
Explanation:
The equation that gives the speed of sound in ar as a function of the air temperature is the following:

where
T is the temperature of the air, measured in Celsius degrees
In this problem, we want to find the speed of sound in ar for a temperature of

Substituting into the equation, we find:

So, the velocity of sound in at 300C is 511.3 m/s.
Learn more about sound waves:
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Explanation:
Only few supernova are observed in our galaxy -
Type II supernovae ( i.e. the explosions of the massive stars ) occurred in the Milky Way, and they might be hidden by the intervening dust if they are located in the more distant parts of our Galaxy .
Type Ia supernovae , which need a white dwarf star in the binary star system , are brighter than the type II supernovae , but some of them could also happen in the older parts of Galaxy which are hidden due to the buildup of the dust and gas .