Astronomers use a special kind of instrument called a spectrometer to analyze stars. Spectrometers can determine what stars are made of even if the stars are very far away. How is it possible for spectrometers to do this?

An air-filled capacitor is formed from two long conducting cylindrical shells that are coaxial and have radii of 26 mm and 103 mm. the electric potential of the inner conductor with respect to the outer conductor is - 700 v (k = 1/4πε 0 = 8.99 × 109 n · m2/c2) the energy stored in a 1.0-m length of this capacitor is closest to