Archaeopteryx,a transitional fossil between birds and reptiles,was discovered from rocks of which of the following periods?

Regarding the molecular orbital $(MO)$ energy levels for homonuclear diatomic molecules, the $\text{INCORRECT}$ statement$(s)$ is$($are$)$
$(A)$ Bond order of $Ne _2$ is zero.
$(B)$ The highest occupied molecular orbital $\text{(HOMO)}$ of $F_2$ is $\sigma$-type.
$(C)$ Bond energy of $O _2^{+}$is smaller than the bond energy of $O _2$.
$(D)$ Bond length of $Li _2$ is larger than the bond length of $B _2$

What is obtained when an aqueous solution of aluminum chloride is heated to dryness?

Two long conductors,separated by a distance $d$,carry currents $I_1$ and $I_2$ in the same directions. They exert a force $F$ on each other. Now,the current in one of them is increased to two times its original value and its direction is reversed. The distance is also increased to $3d$. The new value of the force between them is:

If the slope of one of the lines in the pair of lines $8x^2 + axy + y^2 = 0$ is thrice the slope of the other line,then $a =$

Five moles of hydrogen initially at $STP$ is compressed adiabatically so that its temperature becomes $673 \, K$. The increase in internal energy of the gas, in kilo joule is $(R=8.3 \, J/mol-K; \gamma=1.4$ for diatomic gas$)$