Correct Answer - Option 2 : rubber

**Explanation****:**

**Poisson's ratio:**

Poisson's ratio is the ratio of lateral strain to longitudinal strain. Mathematically is given by,

\(μ = -\frac{Lateral\ strain}{Longitudinal \ Strain}\)

A negative sign in the formula is to make the ratio positive.

Material |
Poisson's Ratio (μ) |

Gold |
0.44 |

Magnesium |
0.35 |

**Copper** |
**0.33** |

**Rubber** |
**0.4999** |

Steel |
0.30 |

Concrete |
0.20 |

**iron** |
**0.21-0.29** |

**Wood** |
**0.18-0.43** |

The Poisson ratio is the property of the material.