In green plants,cell elongation in the internodal regions is caused by which of the following?

Four massless springs whose force constants are $2k, 2k, k$ and $2k$ respectively are attached to a mass $M$ kept on a frictionless plane (as shown in figure). If the mass $M$ is displaced in the horizontal direction,then the frequency of oscillation of the system is

$A$ light wave is incident normally on a slit of width $24 \times 10^{-5} \ cm$. The angular position of the second dark fringe from the central maxima is $30^{\circ}$. What is the wavelength of light in $\mathring{A}$?

The point collinear with $(1, -2, -3)$ and $(2, 0, 0)$ among the following is

The mass of a planet is half that of the earth and the radius of the planet is one-fourth that of earth. If we plan to send an artificial satellite from the planet,the escape velocity will be,(escape velocity on earth $v_e = 11 \ km \ s^{-1}$) (in $km \ s^{-1}$)

Which of the following is a biodegradable polymer?