the speed of light is 3*100000000. its speed is the glass is 2*100000000. calculate its refractive index

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?

Asample of a gaseous substance changes into a liquid

Lymphocytes known as blastocysts make antibodies that fight infection. select the best answer from the choices provided t f