Which of the following lacks a capsid?

In a compound microscope,the focal length of the objective lens is $1.2 \ cm$ and the focal length of the eyepiece is $3.0 \ cm$. When the object is kept at $1.25 \ cm$ in front of the objective,the final image is formed at infinity. The magnifying power of the compound microscope is:

The oxidation number of $Pt$ in $[Pt(C_2H_4)Cl_3]^-$ is

The most appropriate magnetization $M$ versus magnetising field $H$ curve for a paramagnetic substance is

An ideal gas expands isothermally from a volume $V_1$ to $V_2$ and then is compressed to the original volume $V_1$ adiabatically. The initial pressure is $P_1$ and the final pressure is $P_3$. The total work done is $W$. Then:

One mole of alkene $\underline{X}$ on ozonolysis gave one mole of acetaldehyde and one mole of acetone. The $IUPAC$ name of $\underline{X}$ is