Haemocoel is found in

If $\theta = \frac{\pi}{6}$,then the $10^{\text{th}}$ term of the series $1 + (\cos \theta + i \sin \theta)^1 + (\cos \theta + i \sin \theta)^2 + \dots$ is

If $\alpha+\beta+\gamma=2 \theta$,then $\cos \theta+\cos (\theta-\alpha)+\cos (\theta-\beta)+\cos (\theta-\gamma)$ is equal to

The jawless vertebrate is

The angle between the lines whose direction cosines satisfy the equations $l+m+n=0$ and $l^2+m^2-n^2=0$ is

Two cylinders $A$ and $B$ fitted with pistons contain equal amounts of an ideal diatomic gas at $300\,K$. The piston of $A$ is free to move,while that of $B$ is held fixed. The same amount of heat is given to the gas in each cylinder. If the rise in temperature of the gas in $A$ is $30\,K$,then the rise in temperature of the gas in $B$ is .... $K$.