Bundle of His is a part of which one of the following organs in humans?

If $R$ is a relation from a finite set $A$ having $m$ elements to a finite set $B$ having $n$ elements,then the number of relations from $A$ to $B$ is

The equation of the normal to the curve $y=x \log x$,which is parallel to the line $2x-2y+3=0$,is

The negation of the statement pattern $\sim p \vee (q \rightarrow \sim r)$ is

In a $\triangle ABC$,$a^2 \sin 2C + c^2 \sin 2A$ is equal to (in $\Delta$)

The angle of elevation of an object on a hill is observed from a certain point in the horizontal plane through its base to be $30^{\circ}$. After walking $120 \ m$ towards it on level ground,the angle of elevation is found to be $60^{\circ}$. The height of the object (in metres) is: