The $IUPAC$ name of $(CH_3)_2CH-CH_2-CH_2Br$ is

In a compound microscope,the focal lengths of two lenses are $1.5 \, cm$ and $6.25 \, cm$. An object is placed at $2 \, cm$ from the objective lens and the final image is formed at $25 \, cm$ from the eye lens. The distance between the two lenses is.......$cm$.

How many litres of oxygen (at $STP$) are required for complete combustion of $39 \text{ g}$ of liquid benzene? (Atomic weights: $C=12, O=16, H=1$)

Vegetative propagation in $Pistia$ occurs by:

$A$ transverse wave is described by the equation $y = y_0 \sin 2\pi \left( ft - \frac{x}{\lambda} \right)$. The maximum particle velocity is equal to four times the wave velocity if:

$A$: The $O-O$ bond length in $H_2O_2$ is smaller than that in $O_2F_2$.
$R$: $H_2O_2$ is an ionic compound.