Circumferential and longitudinal strains in a cylindrical boiler under steam pressure are ε1 and ε2 respectively. Change in volume of the boiler cylinder per unit volume will be
1
ε1 + 2ε2
2
\(\varepsilon_1 \varepsilon_2^2\)
3
2ε1 + ε2
4
\(\varepsilon_1^2 \varepsilon_2\)