The illumination of an object by a light source is directly proportional to the strength of the source and inversely proportional to the square of the distance from the source. if two light sources, one four times as strong as the other, are placed 14 ft apart, how far away from the stronger light source should an object be placed on the line between the two sources so as to receive the least illumination? (round your answer to two decimal places.)

Along wire of diameter 1 mm is submerged in an oil bath of temperature ∞ 31°c. the wire has an electrical resistance per unit length of 0.01 ω/m. if a current of 103 a flows through the wire and the convection coefficient is 500 w/m2·k, what is the steady-state temperature of the wire? from the time the current is applied, how long does it take for the wire to reach a temperature that is within 1°c of the steady-state value? the properties of the wire are 8000 kg/m3, 500 j/kg·k, and 20 w/m·k.