Which of the following oxides is amphoteric?

Find the equation of the parabola whose axis is parallel to the $y$-axis and which passes through the points $(0, 4), (1, 9),$ and $(4, 5)$.

$A$ solid sphere,a hollow sphere,and a ring are released from the top of an inclined plane (frictionless) so that they slide down the plane. Then,the maximum acceleration down the plane is for (no rolling):

Which of the following halogen oxides is ionic?

The magnetic needle of a tangent galvanometer is deflected at an angle $30^{\circ}$ due to a magnet. The horizontal component of the Earth's magnetic field is $0.34 \times 10^{-4} \text{ T}$,which is along the plane of the coil. The magnetic field due to the magnet is:

If $P(A \cup B)=0.8$ and $P(A \cap B)=0.3$,then $P(\bar{A})+P(\bar{B})$ is equal to: