If the momentum of an electron is changed by $\Delta p$,then the de-Broglie wavelength associated with it changes by $0.50\%$. The initial momentum of the electron will be

$A$ 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:

Two blocks of masses $1 ~kg$ and $2 ~kg$ are connected by a metal wire going over a smooth pulley as shown in the figure. The breaking stress of the metal is $2 \times 10^9 ~N/m^2$. What should be the minimum radius of the wire used if it is not to break? Take $g = 10 ~m/s^2$.

Which one of the following equations represents the variation of viscosity coefficient $(\eta)$ with temperature $(T)$?

Which of the following amines undergoes acylation reaction?

The result after adding $3.8 \times 10^{-6}$ and $4.2 \times 10^{-5}$ with due regard to significant figures is: