If $A = \{x : x \text{ is a multiple of } 3\}$ and $B = \{x : x \text{ is a multiple of } 5\}$,then $A - B$ is ($\bar{A}$ means complement of $A$).

In an electrochemicalcell, dichromate ions in aqueous acidic medium are reduced to $Cr ^{3+}$. The current $($in amperes$)$ that flows through the cell for $48.25$ minutes to produce $1$ mole of $Cr ^{3+}$ is $....$ . Use: $1$ Faraday $=96500 C mol ^{-1}$

In angiosperms,the functional megaspore develops into which of the following?

The total number of nitrogenous bases in the human genome is estimated to be about

$A$ square loop of area $25 \, cm^2$ has a resistance of $10 \, \Omega$. This loop is placed in a uniform magnetic field of magnitude $40 \, T$. The plane of the loop is perpendicular to the magnetic field. The work done in pulling the loop out of the magnetic field slowly and uniformly in one second will be:

Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen,sulphur and halogens.