$A$ black body has a maximum wavelength ${\lambda _m}$ at a temperature of $2000 \; K$. Its corresponding wavelength at a temperature of $3000 \; K$ will be:

Keto-enol tautomerism is not observed in

The number and type of bonds between $2$ carbon atoms in $CaC_2$ are:

$A$ crystal is made up of metal ions $M_1$ and $M_2$ and oxide ions. Oxide ions form a $ccp$ lattice structure. The cation $M_1$ occupies $50 \%$ of octahedral voids and the cation $M_2$ occupies $12.5 \%$ of tetrahedral voids of the oxide lattice. The oxidation numbers of $M_1$ and $M_2$ are,respectively:

In biennial plants,the number of carpels is normally:

Read the following five statements ($a$ to $e$) and select the option with all correct statements:
$(a)$ Mosses and Lichens are the first organisms to colonise a bare rock.
$(b)$ $Selaginella$ is a homosporous pteridophyte.
$(c)$ Coralloid roots in $Cycas$ have $VAM$ mycorrhizae.
$(d)$ Main plant body in bryophytes is gametophytic,whereas in pteridophytes it is sporophytic.
$(e)$ In gymnosperms,male and female gametophytes are present within sporangia located on sporophyte.