Why is the distance between stars expressed in light years ? What do you understand by the statement that a star is eight light years away from the Earth ?

What do you understand by amniocentesis ? Why is there a statutory ban on this ? Give reason

What do you understand from the term 'Refractive index' of a medium or a substance ?

What do you understand by the following statements ? enthalphy of formation of nitric oxide is +9.7 kJ.

What is the distance in km of a quasar from which light takes 3.0 billion years to reach us.

What is the distance in km of a quasar from which light takes 3.0 billion years to reach us.

A telescope of aperture 0.15 m is used to view two heavenly separated by a certain linear distance. If the distance of these two is 1 million light years from the earth and the wavelength of light emitted is 449 nm, the calculate the linear separation between them.