$\left|\begin{array}{lll}24 & 25 & 26 \\ 25 & 26 & 27 \\ 26 & 27 & 27\end{array}\right|$ is equal to

Which of the following ethers is a liquid at room temperature?

Which of the following is an example of a ketohexose?

The area (in square units) of the triangle formed by $x+y+1=0$ and the pair of straight lines $x^2-3xy+2y^2=0$ is

The electric field of a plane electromagnetic wave varies with time with an amplitude of $2 \, Vm^{-1}$ propagating along the $z$-axis. The average energy density of the magnetic field (in $J \, m^{-3}$) is:

Copper sulphate is prepared by blowing a current of air through copper scrap and dilute $H_2SO_4$. Dilute $HNO_3$ is also added: