Which vegetable was absent in India before the arrival of European explorers?

In a playground,there is a merry-go-round of mass $120 \ kg$ and radius $4 \ m$. The radius of gyration is $3 \ m$. $A$ child of mass $30 \ kg$ runs at a speed of $5 \ m/s$ tangent to the rim of the merry-go-round when it is at rest and then jumps on it. Neglecting friction,find the angular velocity of the merry-go-round and child in $rad/s$.

The monomers used in the production of nylon-$6,6$ are

The numerical value of the charge on either plate of the capacitor $C$ shown in the figure is

Which of the following oxides is different from the other three oxides?