$A$ uniform rod of mass $M$ and length $L$ is placed on a smooth horizontal surface. $A$ horizontal force $F$ is applied at one end of the rod perpendicular to its length. The acceleration of the centre of mass of the rod is:

Ectophloic siphonostele is found in ...........

The eccentricity of the ellipse $x^2+4y^2+2x+16y+13=0$ is

In the figure $(a)$,half of the meter scale is made of wood while the other half is made of steel. The wooden part is pivoted at $O$. $A$ force $F$ is applied at the end of the steel part. In figure $(b)$,the steel part is pivoted at $O'$ and the same force is applied at the wooden end (in a horizontal plane).

Which of the following reagents will convert glycerol into acrolein?

The correct order of the $O-O$ bond length in $O_2, H_2O_2$,and $O_3$ is