In order to measure the properties of a battery, several resistors are connected to the battery in series and the terminal voltage is measured. In the first case, the resistor has resistance R1 = 3.5 Ω and the terminal voltage is ΔV1 = 2.9 V. In the second case, the resistor has resistance R2 = 77 Ω and the terminal voltage ΔV2 = 7.5 V. Required:
Find the numerical value of r in Ω.

Asun-sized star will spend most of its lifetime as a: white dwarf red giant protostar main-sequence star

Which of the following statements comparing electron microscopy and light microscopy is false? which of the following statements comparing electron microscopy and light microscopy is false? both the electron microscope and the light microscope use the same wavelengths for illumination. images produced by light microscopes can be in color, whereas electron microscope images are black and white unless they are artificially colored. the electron microscope has greater resolution than the light microscope. electron microscopes can allow examination of viruses and internal cell structures, whereas light microscopes are limited to objects that are 0.5 micrometers and larger. request answer

The path of a satellite orbiting the earth causes it to pass directly over two tracking stations a and b, which are 51 miles apart. when the satellite is on one side of the two stations, the angles of elevation at a and b are measured to be 87 degrees and 84 degrees, respectively. (a) how far is the satellite from station a? (b) how high is the satellite above the ground?