One gas bleaches the colour of flowers by reduction,while the other by oxidation,the two gases respectively are

Which of the following crops contain recalcitrant seeds?

The radiation emitted by a star $A$ is $10000$ times that of the sun. If the surface temperatures of the sun and the star $A$ are $6000 \ K$ and $2000 \ K$ respectively,the ratio of the radii of the star $A$ and the sun is : (in $: 1$)

$A$ person observes the top of a tower from a point $A$ on the ground. The angle of elevation of the tower from this point is $60^{\circ}$. He moves $60 \ m$ in the direction perpendicular to the line joining $A$ and the base of the tower. The angle of elevation of the tower from this new point is $45^{\circ}$. Then,the height of the tower (in metres) is

Two Carnot engines $A$ and $B$ are operated in succession. The first one,$A$,receives heat from a source at $T_1 = 800\, K$ and rejects heat to a sink at $T_2\, K$. The second engine,$B$,receives the heat rejected by the first engine and rejects heat to another sink at $T_3 = 300\, K$. If the work outputs of the two engines are equal,then the value of $T_2$ is ...... $K$.

When $NaCl$ is dissolved in water,the sodium ion becomes