A completely transparent material will be invisible in vacuum when its refractive index is

A completely transparent material will be invisible in vacuum when its refractive index mu is

A completely transparent material will be invisible in vacuum when its refractive index mu is _____

A completely transparent material will be invisible in vacuum when its refractive index mu is _____

A completely trasnparent material will be invisible in vaccum when its refractive index mu is _________.

A complete transparent object is invisible ir free space, then what is its refractive index ?

If a completely transparent object has to be made totally invisible in vacuum, what should be the value of its refractive index?

The speed of light in a transparent medium is 0.6 times that of its speed in vacuum. What is the refractive index of the medium?

A biconcave lens made of transparent material of refractive index 1.25 is immersed in water of refractive index 1.33 . Will the lens behave as a convering or diverging lens? Given reason.