Who invented $X-$ rays? 

Who produced electromagnetic waves for the first time ? 

Cathode rays and canal rays produced in a certain discharge tube are deflected in the same direction if

Cathode rays enter into a uniform magnetic field perpendicular to the direction of the field. In the magnetic field their path will be

Which of the following will have the least value of $\frac{q}{m}$

The colour of the positive column in a gas discharge tube depends on