What is the size of $Wolffia$ $globosa$?

If work $W$ is done in blowing a bubble of radius $R$ from a soap solution,then the work done in blowing a bubble of radius $2R$ from the same solution is

$A$ metal $M$ readily forms its sulphate $MSO_4$,which is water soluble. It forms oxide $MO$ which becomes inert on heating. It forms insoluble hydroxide which is soluble in $NaOH$. The metal $M$ is

The symbiotic association between algal and fungal components is known as ......

Two bodies are thrown up at angles of $45^{\circ}$ and $60^{\circ}$,respectively,with the horizontal. If both bodies attain the same vertical height,then the ratio of velocities with which these are thrown is:

Two point white dots are $1 \, mm$ apart on black paper. They are viewed by an eye with a pupil diameter of $3 \, mm$. Approximately,what is the maximum distance at which these dots can be resolved by the eye? (Take $\lambda = 500 \, nm$)