List of practice Questions

The dipole moment in case of $BeF_2$ is zero. The two equal bond dipoles point in opposite directions and cancel the effect of each other.
: The bridges declared unsafe after a long use. : Elastic strength of bridges loses with time.
The centre of gravity of a body coincides with its centre of mass only if the gravitational field does not vary from one part of the body to the other. Centre of gravity is independent of the gravitational field
:The centre of mass of a body may lie where there is no mass. The centre of mass has nothing to do with the mass.
The characteristics of cathode rays do not depend upon the material of electrodes and the nature of the gas present in the cathode ray tube. Cathode rays consist of negatively charged particles, called electrons.
The alternate type of phyllotaxy is the arrangement of leaves in which a single leaf arises at each node in alternate manner. The alternate type of phyllotaxy is seen in China rose and mustard plant.
The atomic size generally increases across a period and decreases down the group. Atomic size depends upon valence shell electronic configuration.
The back emf in a dc motor is maximum when the motor has just been switched on When motor is switched on it has maximum speed
Test cross is the cross between the $F_1$ progeny and either of the parent types. Back cross is the cross between $F_1$ progeny and the double recessive genotype.
The accelerated motion of an object may be due to change in magnitude of velocity or direction of velocity or both. Acceleration can be produced only by change in the magnitude of the velocity.
The acrocentric chromosome has centromere at the terminal position The metacentric chromosome has centromere slightly away from the middle of the chromosome
The alimentary canal of the frog is short Frogs are carnivores
Stems of some plants protea them from browsing animals. Axillary buds of stems of these plants are modified into thorns.
: Sun looks reddish at sunrise and sunset. : Sun rays have to pass through a larger distance in atmosphere.
Superoxides of alkali metals are paramagnetic. Superoxides contain $O_2^-$ ion which has one unpaired electron.
Tendons attach one bone to another bone Ligaments attach skeletal muscles to bones
Sino-atrial node $(SAN)$ is called the pacemaker. $SAN$ generates the maximum number of action potentials and is responsible for initiating and maintaining the rhythmic contractions of the heart
Smooth muscles are known as involuntary muscles. Smooth muscles are controlled by autonomic nervous system
Soluble fluoride is often added to drinking water to bring its concentration up to $1\, ppm$. $F^{-}$ ion concentration above $2 \,ppm$ causes brown mottling of teeth.
Sponges exhibit cellular level of organisation. In sponges, cells are arranged as loose cell aggregates.
$SiC$ has higher melting point than $NaCl$. $SiC$ has stronger electrostatic forces of attraction.
Quartz glass is crystalline solid and quartz is an amorphous solid. Quartz glass has long range order.
Renal threshold of glucose is said to be $180 mg/100 mL$ Glucose starts appearing in the urine when its blood level exceeds $180 mg/100 \,mL$ of blood
Rudolf Virchow modified the hypothesis of cell theory given by Schleiden and Schwann Cell theory says that all cells arise from pre existing cells
Primary growth of the plants contributes to the elongation of the plants along their axis. Root apical meristem and shoot apical meristem are responsible for primary growth of the plants.