True or false Almost all of Earth's atmosphere is created through the process of photosynthesis.

What explosion in the upper solar atmosphere releases about as much energy as millions of 100-megaton hydrogen bombs exploding simultaneously?

The frequency of a tuning fork can be found by the method shown. a long tube open at both ends is submerged in a beaker of water, and the vibrating tuning fork is placed near the top of the tube. the length l of the air column is adjusted by moving the tube vertically. the sound waves generated by the fork are reinforced when the length of the air column corresponds to one of the resonant frequencies of the tube. the smallest value for l for which a peak occurs in sound intensity is 7 cm. l what is the frequency of the tuning fork? the speed of sound in air is 345 m/s. answer in units of hz

Figure shows a simple cathode-ray tube. a beam of particles, emitted by the cathode, strikes the centre of the screen. a. why the cathode must be heated? b. what is the principal energy change that occurs when the beam strikes the screen? c describe and explain what you would expect if the two deflecting plates g and h were connected to an alternating voltage supply