Which of the following statement(s) is/are true about the state of a body in plane strain condition?
P: All the points in the body undergo displacements in one plane only, for example the $x$ -y plane, leading to $\varepsilon_{z z}=\gamma_{x z}=\gamma_{y z}=0$
Q: All the components of stress perpendicular to the plane of deformation, for example the x-y plane, of the body are equal to zero, i.e. $\sigma_{z z}=\tau_{x z}=\tau_{y z}=0$ R: Except the normal component, all the other components of stress perpendicular to the plane of deformation of the body, for example the $\mathrm{x}$ -y plane, are equal to zero, i.e. $\sigma_{z z} \neq 0$, $\tau_{x z}=\tau_{y z}=0$
(A) $\mathrm{P}$ only
(B) $\mathrm{Q}$ only
(C) $\mathrm{P}$ and $\mathrm{Q}$
(D) $\mathrm{P}$ and $\mathrm{R}$
Which of the following statement(s) is/are true about the state of a body in plane strain condition?
P: All the points in the body undergo displacements in one plane only, for example the $x$ -y plane, leading to $\varepsilon_{z z}=\gamma_{x z}=\gamma_{y z}=0$
Q: All the components of stress perpendicular to the plane of deformation, for example the x-y plane, of the body are equal to zero, i.e. $\sigma_{z z}=\tau_{x z}=\tau_{y z}=0$ R: Except the normal component, all the other components of stress perpendicular to the plane of deformation of the body, for example the $\mathrm{x}$ -y plane, are equal to zero, i.e. $\sigma_{z z} \neq 0$, $\tau_{x z}=\tau_{y z}=0$
(A) $\mathrm{P}$ only
(B) $\mathrm{Q}$ only
(C) $\mathrm{P}$ and $\mathrm{Q}$
(D) $\mathrm{P}$ and $\mathrm{R}$