For a first order reaction,the concentration of reactant was reduced from $0.03 \ mol \ L^{-1}$ to $0.02 \ mol \ L^{-1}$ in $25 \ min$. What is its rate (in $mol \ L^{-1} \ s^{-1}$)?

The variance of $20$ observations is $5$. If each observation is multiplied by $2$,then the variance of the resulting observations is:

The mass of a spaceship is $1000\,kg$. It is to be launched from the earth's surface out into free space. The values of $g$ and $R$ (radius of earth) are $10\,m/s^2$ and $6400\,km$ respectively. The required energy for this work will be:

Read the following statements carefully and select the correct statements.
$(1)$ The wheat variety $Atlas-66$ has high protein content.
$(2)$ $SCP$ is an alternative source of protein for human and animal nutrition.
$(3)$ Plants developed through micropropagation are genetically different from the parent plant.
$(4)$ Semi-dwarf rice varieties were developed from $IR-8$ and $Taichung Native-1$.

Among the following compounds,which one is not responsible for the depletion of the ozone layer?

In an astronomical telescope in normal adjustment,a straight black line of length $L$ is drawn on the inside part of the objective lens. The eyepiece forms a real image of this line. The length of this image is $I$. The magnification of the telescope is