List of top Questions asked in AIIMS

Mass spectrometric analysis of potassium and argon atoms in a Moon rock sample shows that the ratio of the number of (stable) ${ }^{40} Ar$ atoms present to the number of (radioactive) ${ }^{40} K$ atoms is $10.3$. Assume that all the argon atoms were produced by the decay of potassium atoms, with a half-life of $1.25 \times 10^{9} yr$. How old is the rock?

Litharge is chemically

In the diagram shown below all three rods are of equal length $L$ and equal mass $M$. The system is rotated such that rod $B$ is the axis. What is the moment of inertia of the system?

In the change $ {[Cu(H2O)6]^2+ ->[HCl] }[CuC(H_2O)_5]^+$, the colour changes from

If $ AgI $ crystallizes in zinc blende structure with $I^{-}$ ions at lattice points. What fraction of tetrahedral voids is occupied by $Ag^{+}$ ions?

If a solid sphere of mass $1 \,kg$ and radius $0.1\, m$ rolls without slipping at a uniform velocity of $1\, m/s$ along a straight line on a horizontal floor, the kinetic energy is

Hydrogen can be prepared by the action of dil $H_{2}SO_{4}$ on

Cyanogen gas is obtained in the reaction

Composite fruit develops from

Cellulose, the most important constituent of plant cell wall is made up of

Voltmeter is connected in parallel with the circuit Resistance of a voltmeter is very large.

: The true nucleus is generally absent in E. coli and other prokaryotes : An undifferentiated, unorganized fibrillar nucleus without any limiting membrane is observed in prokaryotic cells

The position of an element in periodic table after emission of one $\alpha$ - and two $\beta$ - particles remains unchanged. Emission of one $\alpha$ - and two $\beta$ - particles give isotope of the element which acquires same position in periodic table.

: The conversion of fresh precipitate to colloidal state is called peptization. : It is caused by addition of common ions.

Secreting hypotonic urine is effective in reducing urinary loss of water. Hypotonic urine is more concentrated and higher in osmotic pressure than the blood.

Ozone is an allotrope of oxygen. Oxygen is bluish colour liquid and in singlet state it is more paramagnetic.

Optical fibres are used for telecommunication Optical fibres are based on the phenomenon of total internal reflection.

NAND is a universal gate. It can be used to describe all other logic gates.

n: Light emitting diode $(LED)$ emits spontaneous radiation. : $LED$ are forward biased p-n junctions.

: $F-F$ bond in $F _{2}$ molecule is strong. : $F$ atom is small in size.

F is more electronegative than Cl F has high electron affinity than Cl.

: Chlorine has higher electron affinity than fluorine. : Chlorine is a poor oxidising than fluorine.

Benzene diazonium salt on boiling with water forms phenol. C $-$ N bond is polar.

: At high pressure, the compression factor $Z$ is $\left(1+\frac{P b}{R T}\right)$. : At high pressure van der Waals' equation is modified as $P(V-b)=R T$.

An astronaut experience weightlessness in a space satellite. When a body falls freely it does not experience gravity.