$A$ telescope has an objective lens of focal length $150 \ cm$ and an eyepiece of focal length $5 \ cm$. If a $50 \ m$ tall tower at a distance of $1 \ km$ is observed through this telescope in normal setting,the angle formed by the image of the tower is $\theta$,then $\theta$ is close to..... (in $^{\circ}$)

The major product of the following reaction is

The height of the cone of maximum volume inscribed in a sphere of radius $R$ is

........ of a reaction cannot be determined experimentally.

Hydrated $AlCl_3$ is used as:

Condenser $A$ has a capacity of $15 \mu F$ when it is filled with a medium of dielectric constant $15$. Another condenser $B$ has a capacity of $1 \mu F$ with air between the plates. Both are charged separately by a battery of $100 V$. After charging,both are connected in parallel without the battery and the dielectric material being removed from condenser $A$. The common potential now is.......$V$