A whistle is often used in dog-­‐‑training exercises and is an integral part of field-­‐‑marking competitions, where signals and commands are relayed to the dog via whistle. Suppose the whistle produces a sound wave with a frequency of 25,100 Hz (outside the range of human hearing) and the propagation speed of sound in air is 343 m/s. 1) What is the wavelength and wave number of this sound from the whistle?
2) Write the wave function for the longitudinal sound wave described above, assuming the amplitude of the sound wave is Smax = 1.57 x 10-­‐‑6 m and it is moving to the right (in the positive x direction).

The wavelength is  

The wave number is  

The wave function is  

Explanation:

From the question we are told that

    The frequency of the sound wave is  

    The speed of the wave is  

The wavelength of the wave is mathematically evaluated as

substituting values

The wave number is  mathematically represented as

substituting values

The general form of  wave function is

given that the amplitude is  

  While which is the angular velocity is  represented as  

  and  k which is the angular wave number is mathematically represented as    

   The wave function becomes  

substituting values

nec chapter 5 contains

c. information on special occupancy areas

nec chapter 6 covers

a. special equipment

which of the following rules contain the words shall or shall not and must be adhered to?

b. mandatory rules

which of the following rules identify actions that are allowed but not required and typically cover options or alternative methods?

c. optional rules

which of the following serves as the introduction to the nec and provides an overview of the book?

a. nec article 90

organizations that test products for safety are

c. nrtls

the nec is published by the

a national fire protection association

the nec is divided into

b. 9 chapters

the nec provides informative annexes for

c. informational materials and examples

two terms from nec article 100 that trainees should become familiar with are

b. labeled and listed

explanation:

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000