When $CO_2$ gas is passed through an aqueous solution of $Na_2CO_3$,what is formed?

The angle between the pair of tangents drawn to the ellipse $3x^2 + 2y^2 = 5$ from the point $(1, 2)$ is:

In the figure shown,the power generated in $y$ is maximum when $y = 5\,\Omega$. Then $R$ is .............. $\Omega$.

$A$ particle is projected up along a rough inclined plane of inclination $45^{\circ}$ with the horizontal. If the coefficient of friction is $0.5$, the acceleration is ($g=$ Acceleration due to gravity).

What is the technique of obtaining a large number of plantlets by tissue culture called?

$A$ and $B$ are two concentric circular loops carrying currents $i_1$ and $i_2$ as shown in the figure. If the ratio of their radii is $1:2$ and the ratio of the magnetic flux densities at the centre $O$ due to $A$ and $B$ is $1:3$,then the value of $\frac{i_1}{i_2}$ will be: