For effective nuclear forces, the distance should be

Size of nucleus is of the order of

Ratio of nuclear radii of ${ }^{135} Cs$ to ${ }^{40} Ca$ is

In the nuclear reaction $_{92}{U^{238}}{ \to _z}T{h^A}{ + _2}H{e^4}$, the values of $A$ and $Z$ are

Consider the following statements ( $X$ and $Y$ stand for two different elements):

$(I)$ ${ }_{32}^{65} X$ and ${ }_{33}^{65} Y$ are isotopes.

$(II)$ ${ }_{42}^{86} X$ and ${ }_{42}^{85} Y$ are isotopes.

$(III)$ ${ }_{85}^{174} X$ and ${ }_{88}^{177} Y$ have the same number of neutrons.

$(IV)$ ${ }_{92}^{235} X$ and ${ }_{94}^{235} Y$ are isobars.

Which of the above statements are correct?

Choose the correct statement