Given below are two statements: one is labelled as Assertion A an… - Vidyadip

MCQ

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$

Assertion $A$ : A spherical body of radius $(5 \pm 0.1)$ $mm$ having a particular density is falling through a liquid of constant density. The percentage error in the calculation of its terminal velocity is $4\,\%$.

Reason $R$ : The terminal velocity of the spherical body falling through the liquid is inversely proportional to its radius.

In the light of the above statements, choose the correct answer from the options given below on :

A
Both $A$ and $R$ are true but $R$ is NOT the correct explanation of $A$
B
Both $A$ and $R$ are true and $R$ is the correct explanation of $A$
C
$A$ is false but $R$ is true
✓
$A$ is true but $R$ is false

✓

Answer

Correct option: D.

$A$ is true but $R$ is false

d
Terminal velocity of a spherical body in liquid

$\Rightarrow V _{ t } \propto r ^2$

$\Rightarrow \frac{\Delta V _{ t }}{ V _{ t }}=2 \cdot \frac{\Delta r }{ r }$

$\Rightarrow \frac{\Delta V _{ t }}{ V _{ t }} \times 100 \%=2 \frac{(0.1)}{5} \times 100=4\,\%$

Also $V_t \propto r^2$

Reason $R$ is false

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from 1. units,dimensions and measurement→1. units,dimensions and measurement — all question types→Physics STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

Two guns $A$ and $B$ can fire bullets at speed $1\, km/s$ and $2\, km/s$ respectively. From a point on a horizontal ground, they are fired in all possible directions. The ratio of maximum areas covered by the bullets fired by the two guns, on the ground is

Two circular discs $\sqrt {2gh} $ and $B$ are of equal masses and thickness but made of metals with densities ${d_A}$ and ${d_B}$ $({d_A} > {d_B})$. If their moments of inertia about an axis passing through centres and normal to the circular faces be ${I_A}$ and ${I_B}$, then

From which Newton's law the other two laws can be derived?

A small ball falling vertically downward with constant velocity $4m/s$ strikes elastically $a$ massive inclined cart moving with velocity $4m/s$ horizontally as shown. The velocity of the rebound of the ball is

A body falling vertically downwards under gravity breaks in two parts of unequal masses. The centre of mass of the two parts taken together shifts horizontally towards:

Two waves represented by $\text{y}=\text{a}\sin(\omega\text{t}-\text{kx})$ and $\text{y}=\text{a}\cos(\omega\text{t}-\text{kx})$ are superposed. The resultant wave will have an amplitude:

A disc of radius $R$ is rolling down an inclined plane whose angle of inclination is $\theta $, Its acceleration would be

Consider a uniform rod of mass $\mathrm{M}=4 \mathrm{m}$ and length $\ell$ pivoted about its centre. A mass $m$ moving with velocity $v$ making angle $\theta=\frac{\pi}{4}$ to the rod's long axis collides with one end of the rod and sticks to it. The angular speed of the rod-mass system just after the collision is

The fundamental frequency of a string stretched with a weight of $4 kg$ is $256 Hz$. The weight required to produce its octave is .... $kg \,wt$

A force $\vec F\, = \,2\hat i\,\, - \,3\hat j\, + 7\hat k\,(N)$ acts on a particle which undergoes a displacement of $\vec S\, = \,7\hat i\,\, + \,3\hat j\, - 2\hat k\,(m)$ . Calculate the work done by force ................ $\mathrm{J}$