How does a light ray behave when it is passed through a lens ?

How does colour of light changes, when passed through any transparent medium ?

What happens to a light ray when it passes through a transparent medium bounded by plane surfaces which are inclined to each other ?

How does red colour change while passing through a prism ?

Explain the phenomenon observed When a beam of light is passed through a colloidal sol.

a) Speed of light is constant in vacuum. b) Speed of light depends on the wavelength of light when it passes through a medium. Which one is correct ? or both ?

A liquid is found to scatter a beam of light but leaves no residance when passed through the filter paper. The liquid can be described as

Explain what is observed (i) when a beam of light is passed through a colloidal sol. (ii) an electrolyte, NaCl is added to hydrated ferric oxide sol. (iii) electric current is passed through a colloidal sol ?