Question

The space between two large horizontal metal plates $6cm$ apart, is filled with a liquid of viscocity $0.8N/m$. A thin plate of surface area $0.01m$ is moved parallel to the length of the plate such that the plate is at a distance of $2m$ from one of the plates and $4cm$ from the other. If the plates moves with a constant speed of $1m{s}^{-1}$, then

• A. the layer of the fluid which is having the maximum velocity, is lying mid-way between the plates
• B. the layers of the fluid, which is in contact with the moving plate, is having the maximum velocity
• C. the layer of the fluid, which is in contact with the moving plate and is on the side of farther plate, is moving with maximum velocity
• D. the layer of the fluid, which is in contact with the moving plate and is on the side of nearer plate, is moving with maximum velocity

Answer 1

The correct option is B the layers of the fluid, which is in contact with the moving plate, is having the maximum velocity

Since at the boundary condition or at fixed plate velocity of fluid is zero. Now velocity will keep on decreasing as we start moving from thin plate to large plate. Fluid at closer to plate will try to move with plate to reduce relative motion between them