In refraction,light waves are bent on passing from one medium to a second medium because,in the second medium,

$(a)$ The refractive index of glass is $1.5$. What is the speed of light in glass? (Speed of light in vacuum is $3.0 \times 10^{8} \; m/s$).
$(b)$ Is the speed of light in glass independent of the colour of light? If not,which of the two colours,red or violet,travels slower in a glass prism?

$A$ tank is filled with water to a height of $16 \text{ cm}$. Find the apparent depth of a needle lying at the bottom of the tank as measured by a microscope. The refractive index of water $(\mu_{w})$ is $\frac{4}{3}$. (in $\text{ cm}$)

In refraction,light waves are bent on passing from one medium to the second medium,because,in the second medium

Frosted glass is widely used for translucent windows. The region where a transparent adhesive tape is stuck over the frosted glass becomes transparent. The most reasonable explanation for this is:

$A$ light wave has a frequency of $4 \times 10^{14} \,Hz$ and a wavelength of $5 \times 10^{-7} \,m$ in a medium. The refractive index of the medium is