# Long answer type question. Describe an experiment to find out Young’s modulus of the material in the form of a long string wire. - Physics

Long answer type question.

Describe an experiment to find out Young’s modulus of the material in the form of a long string wire.

#### Solution

Experimental description to find Young’s modulus:

1. Consider a metal wire suspended from a rigid support. A load is attached to the free end of the wire. Due to this, the deforming force gets applied to the free end of wire in downward direction and it produces a change in length.
Let,
L = original length of wire,
Mg = weight suspended to wire,
l = extension or elongation,
(L + l) = new length of wire
r = radius of the cross-section of wire
2. In its equilibrium position,
"Longitudinal stress" = "Applied force"/"Area of cross section"
= "F"/"A"
= "Mg"/(pi"r"^2)
"Longitudinal strain" = "Change in length"/"Original length" = l/"L"
3. From definition,
"Young’s modulus (Y)" = "longitudinal stress"/"longitudinal strain"
= ("Mg"//pi"r"^2)/(l//"L")
∴ Y = "Mg L"/(pi"r"^2 l)
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#### APPEARS IN

Balbharati Physics 11th Standard Maharashtra State Board
Chapter 6 Mechanical Properties of Solids
Exercises | Q 4. (iii) | Page 112