In an experiment, brass and steel wires of length 1 m each with areas of cross section `1mm^(2)` are used. The wires are connected in series and one end of the combined wire is connected to a rigid support and other end is subjected to elongation. The stress required to produce a net elongation of 0.2 mm is, [Given, the Young’s Modulus for steel and brass are, respectively, `120 xx 10^(9) N//m^(2) and 60 xx 10^(9) N//m^(2)`

Options

A. `1.8xx10^(6)N//m^(2)`
B. `1.2xx10^(6)N//m^(2)`
C. `4.0xx10^(6)N//m^(2)`
D. `0.2xx10^(6)N//m^(2)`

Answer

none

Explanation

None `Deltal=((F)/(Y_(1)A))/(l)+((F)/(Y_(2)A))/(l)=0.2xx10^(-3)`
`(F)/(A)((l)/(Y_(1))+(l)/(Y_(2)))=0.2 xx10^(-3)`
`(F)/(A)((3)/(120xx10^(9)))=0.2xx10^(-3)`
`(F)/(A)=8xx10^(-6)(N)/(m^(2))`