[amp_mcq option1=”free vortex motion” option2=”forced vortex motion” option3=”free vortex at center and forced vortex outside” option4=”forced vortex at center and free vortex outside” correct=”option1″]
The correct answer is: A. free vortex motion.
A free vortex is a vortex in which the fluid particles move in circular paths with the same angular velocity at all radii. This is in contrast to a forced vortex, in which the fluid particles move in circular paths with a decreasing angular velocity as the radius increases.
The motion of air mass in a tornado is a free vortex motion. This is because the air particles in a tornado are all moving in circular paths with the same angular velocity. This is due to the fact that the tornado is a rotating column of air. The air at the center of the tornado is rotating the fastest, while the air at the outside of the tornado is rotating the slowest.
The other options are incorrect because they do not describe the motion of air mass in a tornado accurately. Option B, forced vortex motion, is incorrect because the air particles in a tornado are not moving in circular paths with a decreasing angular velocity as the radius increases. Option C, free vortex at center and forced vortex outside, is incorrect because the air particles in a tornado are all moving in circular paths with the same angular velocity. Option D, forced vortex at center and free vortex outside, is incorrect because the air particles in a tornado are not moving in circular paths with a decreasing angular velocity as the radius increases.