This question was asked in 2012 cbse board exam. Question from RS Aggarwal book chapter volume and surface area of solid, page number 810, exercise 17B, problem number 7.
Deepak BoraNewbie
A copper rod of diameter 2 cm and length 10 cm is drawn into a wire of uniform thickness and length 10 m. Find the thickness of the wire
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Given data,
The radius of the copper rod, R = 2/2 = 1cm
The height of the copper rod, H = 10 cm
The height of the wire, h = 10 m = 1000 cm
Volume of the wire = Volume of the rod
πr²h = πR²H
r²h = R²H
r² * 1000 = 1 * 10
r² = 1/100
r = √[ 1/100]
r = 1/10
r = 0.1 cm
Diameter of the wire = 2r
= 2 * [0.1]
= 0.2 cm
∴ Thickness of the wire = 0.2 cm
∴ Thickness of the wire = 2 mm