Which of the following statements is untrue in regard to sound traveling in air? a. sound waves in the air are transverse and consist of compressions and rarefactions of air molecules. b. as the distance from the earth increases, the sound wave intensity also decreases due to the lessening density. c. during a single vibration of the diaphragm, molecules in the air near it will also complete one vibration. d. the area covered by the wave front increases as the wave advances, but the energy passing through a wave front in a unit of time decreases.

The frequency of vibrations of a vibrating violin string is given by f = 1 2l t ρ where l is the length of the string, t is its tension, and ρ is its linear density.† (a) find the rate of change of the frequency with respect to the following. (i) the length (when t and ρ are constant) (ii) the tension (when l and ρ are constant) (iii) the linear density (when l and t are constant) (b) the pitch of a note (how high or low the note sounds) is determined by the frequency f. (the higher the frequency, the higher the pitch.) use the signs of the derivatives in part (a) to determine what happens to the pitch of a note for the following. (i) when the effective length of a string is decreased by placing a finger on the string so a shorter portion of the string vibrates df dl 0 and l is ⇒ f is ⇒ (ii) when the tension is increased by turning a tuning peg df dt 0 and t is ⇒ f is ⇒ (iii) when the linear density is increased by switching to another string df dρ 0 and ρ is ⇒ f is ⇒

Current from a charged capacitor lights a bulb. as time goes on the brightness of the

How do you know how many valence electrons an atom has?