Using your knowledge of circular (centripetal) motion, derive an equation for the radius r of the circular path that electrons follow in terms of the magnetic field b, the electrons' velocity v, charge e, and mass m. you may assume that the electrons move at right angles to the magnetic field.

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?

Need asap which of these is an example of a hypothesis? (2 points) a. adults were not interviewed b. the investigation was time consuming c. the source of information was biased d. very few teenagers were interviewed scientists in different parts of the world have conducted experiments to find the speed of light in vacuum. if the results of the experiments are identical, they would most likely be (2 points) a.valid b. biased c. unreliable d. non-observable which of these questions can be answered using science? (2 points) a. what is the best career? b. does water exist on venus? c. should the use of automobiles be stopped? d. which is the most interesting subject to study? the models can be best used to (2 points) recreate something which is easily observed in nature prove that all atomic theories have the same meaning demonstrate the transformation of atomic theory into law represent the locations of subatomic particles in different atomic theories 22. (bws.06) scientists earlier believed that the lowest measurable temperature is the freezing point of ice. however, modern scientists believe that temperatures below the freezing point of ice can also exist. what best accounts for these different opinions? (2 points) scientists propose contradictory ideas to include all possibilities scientists come up with different hypotheses without enough evidence scientists propose different ideas to avoid repetition of scientific knowledge scientists having different interests may interpret the same data in different ways based on the graph, what is the most likely mass of an apple chosen randomly from the basket? (2 points) between 0.10 kg and 0.12 kg between 0.12 kg and 0.14 kg between 0.14 kg and 0.16 kg between 0.16 kg and 0.18 kg a scientist studies a model of a widely accepted theory about the position of planets and sun. the model would most likely the scientist to (2 points) prove that the theory would not change in the future demonstrate how the theory can be changed into a law understand facts which cannot be easily observed prove that all other facts about the universe are incorrect one scientist discovered a new theory on the evolution of the universe. what is the next step for the scientist to take? (2 points) transform the results of the theory into universal laws of nature inform the scientific community so they can verify the results call a press conference to make the discovery popular among people encourage scientists worldwide to find an appropriate application for the results the students' observations are listed below. when an iron nail is taken near the north pole (n) of the bar magnet, it is pulled towards the magnet. when an iron nail is taken near the south pole (s) of the bar magnet, it is pulled towards the magnet. the experiment was repeated by several students using different bar magnets. based on the investigations, which of these theories would the students most likely propose? (2 points) magnets attract iron nails the poles of a magnet attract all materials iron nails are attracted towards all materials iron nails have the same properties as magnets

What would people living along the coast in south florida do if there was a hurricane warning? move to locations away from the water flock along coasts to watch the natural phenomenon buy instruments to predict the exact location of the hurricane measure water levels to know the exact time of the hurricane