MCQ
$8$ mercury drops coalesce to form one mercury drop, the energy changes by a factor of
- A$1$
- B$2$
- ✓$4$
- D$6$
✓
Answer
Correct option: C.
$4$
c
(c) As volume remains constant therefore $R = {n^{1/3}}r$
(c) As volume remains constant therefore $R = {n^{1/3}}r$
$\frac{{{\rm{Energy\, of \,big \,drop}}}}{{{\rm{Energy \,of\, small\, drop}}}} = \frac{{4\pi {R^2}T}}{{4\pi {r^2}T}} = \frac{{{R^2}}}{{{r^2}}}$$ = {(8)^{2/3}} = 4$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
$A$ rod of length $1000\, mm$ and coefficient of linear expansion $a = 10^{-4}$ per degree is placed symmetrically between fixed walls separated by $1001\, mm$. The Young’s modulus of the rod is $10^{11} N/m^2$. If the temperature is increased by $20^o C$, then the stress developed in the rod is ........... $MPa$
→Water $\left(\rho=1000 \,kg / m ^3\right)$ and kerosene $\left(\sigma=800 \,kg / m ^3\right)$ are filled in two identical cylindrical vessels. Both vessels have small holes at their bottom. The speed of the water and kerosene coming out of their holes are $v_1$ and $v_2$ respectively. Select the correct alternative
→A clock $S$ is based on oscillations of a spring and a clock $P$ is based on pendulum motion. Both clocks run at the same rate on earth. On a planet having same density as earth but twice the radius then
→A metal sheet with a circular hole is heated. The hole:
A uniformly thick wheel with moment of inertia $I$ and radius $R$ is free to rotate about its centre of mass (see fig). A massless string is wrapped over its rim and two blocks of masses $\mathrm{m}_{1}$ and $\mathrm{m}_{2}\left(\mathrm{m}_{1}>\mathrm{m}_{2}\right)$ are attached to the ends of the string. The system is released from rest. The angular speed of the wheel when $\mathrm{m}_{1}$ descents by a distance $h$ is
→If the pressure of an ideal gas contained in a closed vessel is increased by $0.5\%,$ the increase in temperature is $2K.$ The initial temperature of the gas is ...... $^oC$
→In which of the following decays the element does not change?
A position dependent force $F$ acting on a particle and its force-position curve is shown in the figure. Work done on the particle, when its displacement $0$ to $5\,m$ is ............. $\mathrm{J}$
→A rope is wound round a hollow cylinder of mass $5\,kg$ and radius $0.5\,m.$ ........ $rad/s^2$ is the angular acceleration of the cylinder if the rope is pulled with a force of $20\,N$ ?
→A body sliding on a smooth inclined plane requires $4$ seconds to reach the bottom starting from rest at the top. How much time does it take to cover one-fourth distance starting from rest at the top.............$s$
→