For the study of the helical structure of nucleic acids,the property of electromagnetic radiation generally used is

$A$ $20 \ cm$ length of a certain solution causes right-handed rotation of $38^{\circ}$. $A$ $30 \ cm$ length of another solution causes left-handed rotation of $24^{\circ}$. The optical rotation caused by a $30 \ cm$ length of a mixture of the above solutions in the volume ratio $1:2$ is

Two polaroids $A$ and $B$ are placed in such a way that the pass-axes of the polaroids are perpendicular to each other. Now, another polaroid $C$ is placed between $A$ and $B$, bisecting the angle between them. If the intensity of unpolarised light is $I_0$, then the intensity of the transmitted light after passing through polaroid $B$ will be:

$A$ beam of light $AO$ is incident on a glass slab $(\mu = 1.54)$ in a direction as shown in the diagram. The reflected ray $OB$ is passed through a polaroid. On viewing through the polaroid,we find that on rotating the polaroid: (Given $\tan 57^{\circ} = 1.54$)

$A$ beam of plane polarized light falls normally on a polarizer of cross-sectional area $3 \times 10^{-4} \, m^2$. The flux of energy of the incident ray is $10^{-3} \, W$. The polarizer rotates with an angular frequency of $31.4 \, rad/s$. The energy of light passing through the polarizer per revolution is:

Which property can be used to distinguish between light waves and sound waves?