NEET Practice Questions (MCQs) with Answers & Solutions

The NCERT summary point 3 states: 'In rotation about a fixed axis, every particle of the rigid body moves in a circle which lies in a plane perpendicular to the axis and has its centre on the axis. Every Point in the rotating rigid body has the same angular velocity at any instant of time.'

For rotational equilibrium, the total torque must be zero ($\sum \vec{\tau_i} = 0$). For 'not in translational equilibrium', the total force must be non-zero ($\sum \vec{F_i} \neq 0$). This combination corresponds to the description of partial equilibrium provided in the text, specifically the example with Fig. 6.20(a) where the rod was in rotational equilibrium ($net moment = 0$) but not translational equilibrium ($\sum F \neq 0$).

The text states: 'A number of polyhalogen compounds e.g., dichloromethane, chloroform, iodoform, carbon tetrachloride, freon and DDT have many industrial applications.'

The text mentions: 'Our body produces iodine containing hormone, thyroxine, the deficiency of which causes a disease called goiter.'

The text states: 'However, some of these compounds cannot be easily decomposed and even cause depletion of ozone layer and are proving environmental hazards.'

The text states: 'Synthetic halogen compounds, viz. chloroquine is used for the treatment of malaria; halothane is used as an anaesthetic during surgery.'

The text mentions: 'Chlorine containing antibiotic, chloramphenicol, produced by microorganisms is very effective for the treatment of typhoid fever.'

The text states: 'These may be classified as mono, di, or polyhalogen (tri-,tetra-, etc.) compounds depending on whether they contain one, two or more halogen atoms in their structures.'

The text states: 'The boiling points of organohalogen compounds are comparatively higher than the corresponding hydrocarbons because of strong dipole-dipole and van der Waals forces of attraction.'

The text says: 'Certain fully fluorinated compounds are being considered as potential blood substitutes in surgery.'