Sam is walking through the park. he hears a police car siren moving on the street coming toward him. what happens to the siren sound as it approaches and then passes sam? a. as the siren approaches sam, the frequency of sound waves from the siren increase. as the police car continues past sam, the sound waves decrease in frequency. b. as the police car approaches sam, sound waves from the siren remain constant. as the car continues past sam, the sound waves decrease in frequency. c. as the police car approaches sam, the frequency of sound waves from the siren decrease. as the car continues past sam, the sound waves increase in frequency. d. as the police car approaches sam, the frequency of the sounds waves from the siren increases and continues to increase as the car passes and moves away from sam.

Chapter 23, problem 075 the figure shows a geiger counter, a device used to detect ionizing radiation (radiation that causes ionization of atoms). the counter consists of a thin, positively charged central wire surrounded by a concentric, circular, conducting cylindrical shell with an equal negative charge. thus, a strong radial electric field is set up inside the shell. the shell contains a low-pressure inert gas. a particle of radiation entering the device through the shell wall ionizes a few of the gas atoms. the resulting free electrons (e) are drawn to the positive wire. however, the electric field is so intense that, between collisions with gas atoms, the free electrons gain energy sufficient to ionize these atoms also. more free electrons are thereby created, and the process is repeated until the electrons reach the wire. the resulting "avalanche" of electrons is collected by the wire, generating a signal that is used to record the passage of the original particle of radiation. suppose the radius of the central wire is 24 âµm, the inner radius of the shell 2.3 cm, and the length of the shell 14 cm. if the electric field at the shell's inner wall is 2.8 ă— 104 n/c, what is the total positive charge on the central wire?

What are the applications of electromagnetic waves

Which of the following statement is false ? a. batteries should never be stored on metal trays or outside in the elements)b, battery acid cannot be neutralized)c. do not stack batteries on top of each other)d. never put a damaged battery in a dumpster. i