$A$ polariser is used to

$A$ tower subtends angles $\alpha, 2 \alpha$ and $3 \alpha$ respectively at points $A, B$ and $C$,all lying on a horizontal line through the foot of the tower. Then $\frac{A B}{B C}$ is equal to:

If the angles of a triangle are in the ratio $1: 1: 4$,then the ratio of the perimeter of the triangle to its largest side is

An atomic power nuclear reactor can deliver $300\, MW$. The energy released due to fission of each nucleus of uranium atom $^{235}U$ is $170\, MeV$. The number of uranium atoms fissioned per hour will be

$A$ certain vector in the $xy$-plane has an $x$-component of $4 ~m$ and a $y$-component of $10 ~m$. It is then rotated in the $xy$-plane so that its $x$-component is doubled. Then its new $y$-component is (approximately) (in $~m$)

Which of the following statements is correct for Chlorophyceae?