$A$ body of mass $6 ~kg$ is under a force which causes displacement in it given by $s = \frac{t^2}{4}$ metres,where $t$ is time. The work done by the force in $2$ seconds is: (in $~J$)

The energy of a photon is calculated by

Consider a gas phase reaction which occurs in a closed vessel: $2A \rightarrow 4B + C$. The concentration of $B$ is found to be increased by $5 \times 10^{-3} \ mol \ L^{-1}$ in $10 \ s$. The rate of disappearance of $A$ (in $mol \ L^{-1} \ s^{-1}$) is:

The mid-point of a chord of the ellipse $x^2+4y^2-2x+20y=0$ is $(2, -4)$. The equation of the chord is

The wavelength of radiation emitted is $\lambda_0$ when an electron jumps from the third to the second orbit of a hydrogen atom. For the electron to jump from the fourth to the second orbit of the hydrogen atom,the wavelength of radiation emitted will be

Which of the following organisms possesses a cell wall?