The weight of an empty balloon on a spring balance is w_1. The we… - Vidyadip

MCQ

The weight of an empty balloon on a spring balance is $w_1$. The weight becomes $w_2$ when the balloon is filled with air. Let the weight of the air itself be $w$ .Neglect the thickness of the balloon when it is filled with air. Also neglect the difference in the densities of air inside $\&$ outside the balloon. Then :

A
$w_2 = w_1$
B
$w_2 = w_1 + w$
C
$w_2 < w_1 + w$
✓
$A$ and $C$ both

✓

Answer

Correct option: D.

$A$ and $C$ both

d
The weight of the empty balloon is $\mathrm{W}_{1}$. The weight of the balloon filled with air should be $W_{1}+w$ but the balloon is immersed fully in the air, so a force of buoyancy must act on it so the apparent weight $\mathrm{W}_{2}<\mathrm{W}_{1}+\mathrm{w},$ hence $(c)$ is correct. since the densities of air inside and outside are same so the weight of the displaced air by the balloon will also be w. Thus the apparent weight of air-filled balloon $\mathrm{W}_{2}=$ $\left(\mathrm{W}_{1}+\mathrm{w}\right)-\mathrm{w}=\mathrm{W}_{1} \cdot$ Hence $(\mathrm{a})$ is correct. Other options are not true.

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 9.1 , fluid mechanics→9.1 , fluid mechanics — all question types→Physics STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

The degrees of freedom of a triatomic gas is

In an experiment to determine the acceleration due to gravity $g$, the formula used for the time period of a periodic motion is $T=2 \pi \sqrt{\frac{7(R-r)}{5 g}}$. The values of $R$ and $r$ are measured to be $(60 \pm 1) \mathrm{mm}$ and $(10 \pm 1) \mathrm{mm}$, respectively. In five successive measurements, the time period is found to be $0.52 \mathrm{~s}, 0.56 \mathrm{~s}, 0.57 \mathrm{~s}, 0.54 \mathrm{~s}$ and $0.59 \mathrm{~s}$. The least count of the watch used for the measurement of time period is $0.01 \mathrm{~s}$. Which of the following statement($s$) is(are) true?

($A$) The error in the measurement of $r$ is $10 \%$

($B$) The error in the measurement of $T$ is $3.57 \%$

($C$) The error in the measurement of $T$ is $2 \%$

($D$) The error in the determined value of $g$ is $11 \%$

A black coloured solid sphere of radius $R$ and mass $M$ is inside a cavity with vacuum inside. The walls of the cavity are maintained at temperature $T_0$. The initial temperature of the sphere is $3T_0$. If the specific heat of the material of the sphere varies as $\alpha T^3$ per unit mass with the temperature $T$ of the sphere, where $\alpha $ is a constant, then the time taken for the sphere to cool down to temperature $2T_0$ will be ( $\sigma $ is Stefan Boltzmann constant)

One mole of an ideal gas at $300 \mathrm{~K}$ in thermal contact with surroundings expands isothermally from $1.0 \mathrm{~L}$ to $2.0 \mathrm{~L}$ against a constant pressure of $3.0 \mathrm{~atm}$. In this process, the change in entropy of surroundings $\left(\Delta S_{\text {surr }}\right)$ in $\mathrm{J} \mathrm{K}^{-1}$ is $(1 \mathrm{~L} \mathrm{~atm}=101.3 \mathrm{~J})$

$A$ particle of mass $0.5\, kg$ is rotating in a circular path of radius $2m$ and centrepetal force on it is $9$ Newtons. Its angular momentum (in $J·sec$) is:

Mass is distributed uniformly over a thin square plate. If two end points of diagonal are $(-2, 0)$ and $(2, 2)$, what are the coordinates of centre of mass of plate ?

A gas is expanded isothermally from volume $V_1$ to $V_2$ at a constant temperature $T,$ the work done by the gas in this expansion is:

A given ideal gas with $\gamma = \frac{{{C_p}}}{{{C_v}}} = 1.5$ at a temperature $T$. If the gas is compressed adiabatically to one-fourth of its initial volume, the final temperature will be ..... $T$

In a new system of units energy $(E)$, density $(d)$ and power $(P)$ are taken as fundamental units, then the dimensional formula of universal gravitational constant $G$ will be .......

Two objects of mass $10\,kg$ and $20\,kg$ respectively are connected to the two ends of a rigid rod of length $10\,m$ with negligible mass. The distance of the center of mass of the system from the $10\,kg$ mass is :