Questions in Ray Optics and Optical Instruments

Select	Question
	A thin oil layer floats on water. A ray of light making an angle of incidence of 40° shines on oil layer. The angle of refraction of light ray in water is (${{\mu }_{oil}}=1.45,\,{{\mu }_{water}}=1.33$)
	An object is immersed in a fluid. In order that the object becomes invisible, it should
	When light travels from glass to air, the incident angle is ${{\theta }_{1}}$ and the refracted angle is ${{\theta }_{2}}$. The true relation is
	Velocity of light in a medium is $1.5\times {{10}^{8}}m/s.$ Its refractive index will be
	The frequency of a light ray is $6\times {{10}^{14}}Hz.$Its frequency when it propagates in a medium of refractive index $1.5$, will be
	The refractive indices of water and glass with respect to air are 1.2 and 1.5 respectively. The refractive index of glass with respect to water is
	The wavelength of sodium light in air is 5890 Å. The velocity of light in air is $3\times {{10}^{8}}m{{s}^{-1}}.$ The wavelength of light in a glass of refractive index 1.6 would be close to
	The mean distance of sun from the earth is $1.5\times {{10}^{8}}Km$ (nearly). The time taken by the light to reach earth from the sun is
	Refractive index of air is 1.0003. The correct thickness of air column which will have one more wavelength of yellow light (6000 Å) than in the same thickness in vacuum is
	The wavelength of light in air and some other medium are respectively ${{\lambda }_{a}}$ and ${{\lambda }_{m}}.$ The refractive index of medium is