Which river was declared a "National River of India" in

What device is used to measure electric current?  

If a lens forms an image of magnification -2, what is the nature of the image?

Consider the following two statements

(A) Kirchhoff's junction law follows from the conservation of charge.

Which instrument is used to measure the moisture content in the air?

In a spring-block system executing SHM, at displacement x= A/2, the ratio of kinetic to potential energy is:

The colour of sky appears blue due to –

What is the unit of the refractive index?

Let the electric field part of an electromagnetic wave is E = {(2.3 N/C) cos [(1.2 rad/m) y + (2.4 × 10⁸ rad/s)t]} î.