In a meter bridge, as shown in the figure, it is given that resistance $$Y = 12.5\,\,\Omega $$ and that the balance is obtained at a distance $$39.5$$ $$cm$$ from end $$A$$ (by Jockey J). After interchanging the resistances $$X$$ and $$Y$$, a new balance point is found at a distance $${l_2}$$ from end $$A.$$ What are the value of $$X$$ and $${l_2}$$ ?

A particle is oscillating on the $$X$$-axis with an amplitude $$2$$ $$cm$$ about the point $${x_0} = 10\,cm,$$ with a frequency $$\omega $$. A concave mirror of local length $$5$$ $$cm$$ is placed at the origin (see figure).


Identify the correct statements.

A force of $$40$$ $$N$$ acts on a point $$B$$ at the end of an $$L$$-shaped object, as shown in the figure. The angle $$\theta $$ that will produce maximum moment of the force about point $$A$$ is given by :

A charge $$Q$$ is placed at a distance $$a/2$$ above the center of the square surface of edge a as shown in the figure.


The electric flux through the square surface is