알맞은 단어로 빈칸 채우기 1)물체가 한 번의 진동을 완료하는 데 걸리는 시간을
2)소리의 크기는 진동의 에 의해 결정됩니다.
3)주파수 단위는 입니다.
4)원치 않는 소리는 라고 합니다.
5)소리의 날카로움은 진동에 의해 결정됩니다.
I know you can't understand but let me say in English

1)time taken by an object to complete one oscillation is called
2)loudness is determined by the of vibration
3)the unit of frequency is
4)unwanted sound is called
5)shrillness of a sound is determined by the vibration

Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if λ = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.

Water at room temperature of 20.0°c is poured into an aluminum cylinder which has graduation markings etched on the inside. the reading in the graduations is 300.0 cc. the cylinder with the water in it is then immersed in a constant temperature bath at a temperature of 100°c. what is the reading for the level of water on the graduations of the cylinder after the water and the cylinder reach thermal equilibrium with the bath? the volume coefficient of expansion of water is 2.07 x 10^-4 k-1, and the linear coefficient of expansion of aluminum is 23.0 x 10^-6 k-1. a) 305.0 cc b) 304.0 cc c) 303.5 cc d) 303.3 cc e) 304.5 cc

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