Graphical variation of electric field due to a uniformly charged insulating solid sphere of radius $$\mathrm{R}$$, with distance $$r$$ from the centre O is represented by:

Given below are two statements:

Statement I: If heat is added to a system, its temperature must increase.

Statement II: If positive work is done by a system in a thermodynamic process, its volume must increase.

In the light of the above statements, choose the correct answer from the options given below

A charge particle moving in magnetic field B, has the components of velocity along B as well as perpendicular to B. The path of the charge particle will be

The engine of a train moving with speed $$10 \mathrm{~ms}^{-1}$$ towards a platform sounds a whistle at frequency $$400 \mathrm{~Hz}$$. The frequency heard by a passenger inside the train is: (neglect air speed. Speed of sound in air $$=330 \mathrm{~ms}^{-1}$$ )