Which of the following is a cyclic phosphate?

In agarose gel electrophoresis,$DNA$ molecules are separated on the basis of their

The diameter of the objective of a telescope is $1 \ m$. Its resolving limit for light of wavelength $4538 \ \mathring A$ will be:

The spleen is a:

An ideal coil of $10\, H$ is connected in series with a resistance of $5\, \Omega$ and a battery of $5\, V$. After $2\, s$,after the connection is made,the current flowing (in ampere) in the circuit is.

To the free end of a spring hanging from a rigid support,a block of mass $m$ is hung and slowly allowed to come to its equilibrium position. Then the stretching in the spring is $d$. If the same block is attached to the same spring and allowed to fall suddenly,the amount of stretching is: (force constant,$k$)