The same retarding force is applied to stop a train. The train stops after $80 \ m$. If the speed is doubled,then the distance will be

For a normal eye,the cornea of the eye provides a converging power of $40 \ D$ and the least converging power of the eye lens behind the cornea is $20 \ D$. Using this information,the distance between the retina and the cornea-eye lens can be estimated to be ......... $cm$.

Crossing over occurs between which of the following?

The magnifying power of a simple microscope is (when the final image is formed at $D = 25 \ cm$ from the eye):

$A$ particle executes $SHM$ on a straight line path. The amplitude of oscillation is $2 \, cm$. When the displacement of the particle from the mean position is $1 \, cm$,the numerical value of the magnitude of acceleration is equal to the numerical value of the magnitude of velocity. The frequency of $SHM$ is (in $s^{-1}$):

When orthoboric acid is heated,the residue left is ...