[" 19.A electromagnetic radiation of frequency n,wavelength travelling with velocity "v" in air,enters a "],[" glass slab of refractive index.The frequency,wavelength and velocity of radiation in the glass slab "],[" will be respectively: "],[[" 1) "n,(lambda)/(mu),v," 2) "(n)/(mu),lambda,(v)/(mu)," 3) "n,(lambda)/(mu),(v)/(mu)," 4) "(n)/(mu),(lambda)/(mu),(v)/(mu)]]