What are the products formed when phenyl ethyl ether is heated with concentrated $HBr$?

What is the foundation of any breeding program?

If $u(x, y)=y \log x+x \log y$, then $u_x u_y-u_x \log x-u_y \log y+\log x \log y$ is equal to :

What is the gas liberated when alkaline formaldehyde solution is treated with $H_2O_2$?

Two electric charges of $9 \mu C$ and $-3 \mu C$ are placed $0.16 \ m$ apart in air. There will be a point $P$ on the line joining the two charges and in between them where the electric potential is zero. The distance of $P$ from the $9 \mu C$ charge is (in $m$)

$A$ fish looking up through the water sees the outside world,contained in a circular horizon. If the refractive index of water is $\frac{4}{3}$ and the fish is $12 \ cm$ below the water surface,the radius of this circle in $cm$ is