You find an old battery with an unknown EMF, \varepsilonε, and an unknown internal resistance, r. You can characterize the battery using two known resistors and a good ammeter. When you put the battery in series with the first resistor R_1 = 100~\OmegaR 1 =100 Ω, you measure a current through it of I_1 = 0.093 AI 1 =0.093A. You then remove the first resistor and replace it with the second resistor, R_2 = 500~\OmegaR 2 =500 Ω, and now measure a current through it of I_2 = 0.019I 2 =0.019. Calculate the internal resistance of this mystery battery. Assume the ammeter is ideal and has negligible resistance)

In a thunderstorm, charge builds up on the water droplets or ice crystals in a cloud. thus, the charge can be considered to be distributed uniformly throughout the cloud. for the purposes of this problem, take the cloud to be a sphere of diameter 1.00 kilometer. the point of this problem is to estimate the maximum amount of charge that this cloud can contain, assuming that the charge builds up until the electric field at the surface of the cloud reaches the value at which the surrounding air breaks down. this breakdown means that the air becomes highly ionized, enabling it to conduct the charge from the cloud to the ground or another nearby cloud. the ionized air will then emit light due to the recombination of the electrons and atoms to form excited molecules that radiate light. in addition, the large current will heat up the air, resulting in its rapid expansion. these two phenomena account for the appearance of lightning and the sound of thunder. take the breakdown electric field of air to be eb=3.00ă—106n/c. part a estimate the total charge q on the cloud when the breakdown of the surrounding air is reached. express your answer numerically, to three significant figures, using ďµ0=8.85ă—10â’12c2/(nâ‹…m2) .

Which of the following is not a part of the respiratory system? a. pharynx b. trachea c. pancreas d. larynx

The pressure proportional to the area a- inversely b- directly c- increase d-decrease