A raindrop with radius $\mathrm { R } = 0.2 \mathrm {~mm}$ falls from a cloud at a height $\mathrm { h } = 2000 \mathrm {~m}$ above the ground. Assume that the drop is spherical throughout its fall and the force of buoyance may be neglected, then the terminal speed attained by the raindrop is: [Density of water $f _ { \mathrm { w } } = 1000 \mathrm {~kg} \mathrm {~m} ^ { - 3 }$ and Density of air $f _ { \mathrm { a } } = 1.2 \mathrm {~kg} \mathrm {~m} ^ { - 3 } , \mathrm {~g} = 10 \mathrm {~m} / \mathrm { s } ^ { 2 }$ Coefficient of viscosity of air $= 1.8 \times 10 ^ { - 5 } \mathrm {~N} \mathrm {~s} \mathrm {~m} ^ { - 2 }$ ] (1) $250.6 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ (2) $43.56 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ (3) $4.94 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ (4) $14.4 \mathrm {~m} \mathrm {~s} ^ { - 1 }$
A raindrop with radius $\mathrm { R } = 0.2 \mathrm {~mm}$ falls from a cloud at a height $\mathrm { h } = 2000 \mathrm {~m}$ above the ground. Assume that the drop is spherical throughout its fall and the force of buoyance may be neglected, then the terminal speed attained by the raindrop is: [Density of water $f _ { \mathrm { w } } = 1000 \mathrm {~kg} \mathrm {~m} ^ { - 3 }$ and Density of air $f _ { \mathrm { a } } = 1.2 \mathrm {~kg} \mathrm {~m} ^ { - 3 } , \mathrm {~g} = 10 \mathrm {~m} / \mathrm { s } ^ { 2 }$ Coefficient of viscosity of air $= 1.8 \times 10 ^ { - 5 } \mathrm {~N} \mathrm {~s} \mathrm {~m} ^ { - 2 }$ ]\\
(1) $250.6 \mathrm {~m} \mathrm {~s} ^ { - 1 }$\\
(2) $43.56 \mathrm {~m} \mathrm {~s} ^ { - 1 }$\\
(3) $4.94 \mathrm {~m} \mathrm {~s} ^ { - 1 }$\\
(4) $14.4 \mathrm {~m} \mathrm {~s} ^ { - 1 }$