$540\, g$ of ice at $0\,^{\circ}C$ is mixed with $540\, g$ of water at $80\,^{\circ}C$. The final temperature of the mixture is:

$A$ bag contains $2n+1$ coins. It is known that $n$ of these coins have a head on both sides,whereas the remaining $n+1$ coins are fair. $A$ coin is picked up at random from the bag and tossed. If the probability that the toss results in a head is $\frac{31}{42}$,then $n$ is equal to

If $f(x) = \frac{x^2}{x+a}$,then $f^{\prime \prime}(a)$ is equal to

Which of the following instruments is used to measure the rate of transpiration in plants?

In an electroplating experiment,$m \, g$ of silver is deposited when $4 \, A$ of current flows for $2 \, min$. The amount (in $g$) of silver deposited by $6 \, A$ of current for $40 \, s$ will be

In which type of crops is the mass selection method used?