In land plants,the guard cells differ from other epidermal cells in having:

$\operatorname{cosec} 15^{\circ} + \sec 15^{\circ}$ is equal to :

What is the bond angle in $ClO_2$ (OClO) (in $^{\circ}$)?

If $S$ and $S^{\prime}$ are the foci of an ellipse,$B$ is one end of the minor axis and $\angle S B S^{\prime} = 90^{\circ}$,then the eccentricity of that ellipse is

The rate of disintegration of a fixed quantity of a radioactive element can be increased by

$A$ body of mass $5 \ kg$ starts from the origin with an initial velocity $u = 30 \hat{i} + 40 \hat{j} \ ms^{-1}$. When a constant force $F = -(\hat{i} + 5 \hat{j}) \ N$ acts on the body,the time in which the $y$-component of the velocity becomes zero is (in $s$)