Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NTA Abhyas 2020
Exam
NTA Abhyas
Year
2020
Subject
Physics
Chapter
Units and Dimensions

NTA Abhyas 2020 · Physics · Units and Dimensions

A spherical body, of mass& m and radius~ r , is allowed to fall in...

A spherical body, of mass& mm and radius~rr, is allowed to fall in a medium of viscosity ηη . The time in which the velocity of the body increases from~00 to~0.630 . 63 times the terminal velocity~(v)( v ) is called time constant (τ)\left(τ\right) . Dimensionally ττ can be represented as

Options

  1. Amr26πη\dfrac{mr^{2}}{6\pi η}
  2. B6\pimrηg2\sqrt{\dfrac{6\pimrη}{g2}}
  3. Cm6πηrv\sqrt{\dfrac{m}{6\piηrv}}
  4. DNone of these

Correct answer

D. None of these

Step-by-step solution

Time constant is the time of free fall of a body under gravity in the viscous medium, during which the velocity of the body increases to 6363 %& of the terminal velocity. Dimensionally, none of the alternatives have dimensions of time.
Practice Units and Dimensions on Quantrex Academy →

More from Units and Dimensions

In a new system of units, the units of mass, length, time and current are 5 kg, 5 m, 5 s… JEE Advanced 2026A new unit (α) of length is chosen such that it is equal to the speed of light in vacuum.… JEE Main 2026Consider the equation H = (x^p ε^q E^r)/(t^s) , where H= magnetic field; E= electric… JEE Main 2026The percentage error in the calculated volume of a sphere, if there is 2\% error in its… JEE Main 2026Match List - I with List - II. List - I List - II A. Boltzmann constant I. [M^ -1 L^3T^… JEE Main 2026The potential energy of a particle changes with distance x from a fixed origin as V = A x… JEE Main 2026Match List-I with List-II. List-I List-II A. Meter (L) I. (hc)/(G) B. Second (S) II.… JEE Main 2026L , C and R represents physical quantities inductance, capacitance and resistance… JEE Main 2026 Full Units and Dimensions list All NTA Abhyas JEE Main PYQs