The breaking stress for a wire of radius $r$ of a given material is $F \ Nm^{-2}$. The breaking stress for a wire of the same material of radius $2r$ will be:

What is called a brittle material? What is called a ductile material?

According to $C.E.$ van der Waals,the interatomic potential varies with the average interatomic distance $(R)$ as

Two wires as shown in the figure below, made of steel, have a breaking stress of $12 \times 10^8 \text{ N/m}^2$. The area of cross-section of the upper wire is $0.008 \text{ cm}^2$ and that of the lower wire is $0.004 \text{ cm}^2$. The maximum mass that can be added to the pan without breaking any wire is . . . . . . kg. (Take $g = 10 \text{ m/s}^2$)

$A$ force of $10 \,N$ is required to break a wire of radius $1 \,mm$. The force required to break the wire of the same material, but radius $3 \,mm$ will be

The breaking stress of a wire depends upon