What are two ways in which ultrasound technology produces images? A. By absorption of sound waves in the body
B. By using sound in frequencies that reflect off body tissue
C. By measuring the time it takes for reflected sound waves to be detected
D. By determining the frequencies of sound waves

What makes thermal imaging cameras useful? they can detect differences in color. they can detect differences in wave speeds. they can detect differences in temperature. they can detect mechanical waves.

(a) if the pressure in gas is doubled while its volume is held constant, by what factor do (i) vrms and (ii) change? (b) is it possible to boil water at room temperature (20oc) without heating it? explain.

Four point charges each having charge q are located at the corners of a square having sides of length a. find symbolic expressions for the following. (a) the total electric potential at the center of the square due to the four charges (use any variable or symbol stated above along with the following as necessary: ke.) vtotal= (b) the work required to bring a fifth charge p from infinity to the center of the square (use any variable or symbol stated above along with the following as necessary: w=