$ICBN$ stands for

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.......... $cm$.

Which of the following statements is incorrect?

$A$ disc of radius $R$ is made to oscillate about a horizontal axis passing through its periphery. Its time period would be

Work done to increase the temperature of one mole of an ideal gas by $30^{\circ} C$,if it is expanding under the condition $V \propto T^{2/3}$ is,$(R = 8.314 \ J/mol \cdot K)$ (in $J$)

Liquid $X$ is used in a bubble chamber to detect neutral mesons and gamma photons. Then,$X$ is