MCQ
Force necessary to pull a circular plate of $5\, cm$ radius from water surface for which surface tension is $75\, dynes/cm,$ is
- A$30\,dyne$
- B$60 \,dynes$
- C$750 \,dynes$
- ✓$750 \,\pi \,dynes$
✓
Answer
Correct option: D.
$750 \,\pi \,dynes$
d
(d) The total length of the circular plate on which the force will act $ = 2\pi R$
(d) The total length of the circular plate on which the force will act $ = 2\pi R$
Force to pull $ = 2\pi RT = 2 \times \pi \times 5 \times 75 = 750\pi \, dynes$
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
Consider a liquid contained in a vessel. The liquid solid adhesive force is very weak as compared to the cohesive force in the liquid. The shape of the liquid surface near the solid shall be
When there is an electric current through a conducting wire along its length, then an electric field must exist
If a particle is executing simple harmonic motion, then acceleration of particle
A uniform cylinder of length $L$ and mass $M$ having cross-sectional area $A$ is suspended, with its length vertical, from a fixed point by a massless spring, such that it is half submerged in a liquid of density $\sigma $ at equilibrium position. When the cylinder is given a downward push and released, it starts oscillating vertically with a small amplitude. The time period $T$ of the oscillations of the cylinder will be
→A solid cylinder and a solid sphere, having same mass $M$ and radius $R$, roll down the same inclined plane from top without slipping. They start from rest. The ratio of velocity of the solid cylinder to that of the solid sphere, with which they reach the ground, will be.
→The current in a metallic conductor is plotted against voltage at two different temperatures $T_1$ and $T_2$. Which is correct
→The current is flowing in south direction along a power line. The direction of magnetic field above the power line (neglecting earth's field) is
At any instant of time $t$, the displacement of any particle is given by $2 t-1$ ($SI$ unit) under the influence of force of $5 \mathrm{~N}$. The value of instantaneous power is (in SI unit):
→A nucleus at rest disintegrates into two smaller nuclei with their masses in the ratio of $2: 1$. After disintegration they will move :-
→A container, whose bottom has round holes with diameter $0.1$ $mm $ is filled with water. The maximum height in cm upto which water can be filled without leakage will be ........ $cm$
→Surface tension $= 75 \times 10^{-3}$ $ N/m $ and $g = 10$ $ m/s^2$: