$A$ beaker contains $200\, g$ of water. The heat capacity of the beaker is equal to that of $20\, g$ of water. The initial temperature of water in the beaker is $20^\circ C$. If $440\, g$ of hot water at $92^\circ C$ is poured into it,the final temperature (neglecting radiation loss) will be nearest to $^\circ C$.

If $\theta = \frac{\pi}{6}$,then the $10^{th}$ term of the series $1 + (\cos \theta + i \sin \theta) + (\cos \theta + i \sin \theta)^2 + (\cos \theta + i \sin \theta)^3 + \dots$ is equal to:

Which of the following taxonomical aids is being described by the given statements $(i-iv)$?
$(i)$. They are generally established in educational institutes.
$(ii)$. They have collections of preserved plant and animal specimens for study and reference.
$(iii)$. Insects are preserved in boxes after collecting,killing and pinning.
$(iv)$. They often have collections of skeletons of animals too.

$A$ $4 \mu F$ capacitor is charged by a $200 \ V$ battery. It is then disconnected from the supply and connected to another uncharged $2 \mu F$ capacitor. During the process,the loss of energy (in $J$) is:

Fight-or-flight reactions cause activation of

Plaster of Paris,when mixed with the correct amount of water,sets into a solid mass due to the formation of: