A particular person's eardrum is circular, with a diameter of 8.50 mm. (a) How much sound energy (in ) is delivered to an eardrum in one second, at the threshold of human hearing? (The threshold of human hearing is taken to be 1.00 X 10-12 W/m2.) (b) How much sound energy (in )) is delivered to an eardrum in one second, at the pain threshold for human hearing? (The pain threshold occurs at 1.00 W/m , one trillion times as intense as the lowest audible level.) (c) Assume that musicians onstage are exposed to sound that is 10 decibels below the human pain threshold. Over the course of a two-hour concert, how much sound energy (in )) does each ear absorb onstage?(d) Assume that the amplifiers on the stage operate at a combined power of 5,000 Watts, and that 80% of this is converted to sound.

Which is special about a dc circuit ? a. it has both series and parallel components b. it has only series or only parallel components c. charge moves in a single direction d. charge moves back and forth quickly

To understand the electric potential and electric field of a point charge in three dimensions consider a positive point charge q, located at the origin of three-dimensional space. throughout this problem, use k in place of 14? ? 0. part adue to symmetry, the electric field of a point charge at the origin must point from the origin. answer in one word. part bfind e(r), the magnitude of the electric field at distance r from the point charge q. express your answer in terms of r, k, and q. part cfind v(r), the electric potential at distance rfrom the point charge q. express your answer in terms of r, k, and q part dwhich of the following is the correct relationship between the magnitude of a radial electric field and its associated electric potential ? more than one answer may be correct for the particular case of a point charge at the origin, but you should choose the correct general relationship. a)e(r)=dv(r)drb)e(r)=v(r)rc)e(r)=? dv(r)drd)e(r)=? v(r)r

What is the moment of inertia i of this assembly about the axis through which it is pivoted? express the moment of inertia in terms of mr