What is the shortest distance between two points

Modern atomic theory states that the atom is a diffuse cloud of surrounding a small, dense nucleus. a) electron b) neutron c) proton d) quark eliminate

What would the difference of spectral lines emitted by hydrogen gas in distant galaxies which is normally found at a wavelength of 21 cm on earth, be observed at 21.1 centimeters?

Aparticle travels in a circular orbit of radius 21 m. its speed is changing at a rate of 23.1 m/s2 at an instant when its speed is 37.2 m/s. what is the magnitude of the acceleration (in m/s? ) of the particle?