Download App

Fluid Mechanics — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysicsFluid Mechanics1 Mark
MCQ
A barometer kept in an elevator accelerating upward reads 76cm. The air pressure in the elevator is
  • A
    76cm.
  • B
    < 76cm.
  • ✓
    > 76cm.
  • D
    zero.
✓

Answer

Correct option: C.
> 76cm.
When the elevator is going upwards with acceleration a, the effective acceleration is a' = (g + a).
Thus, pressure is given by:
$\text{P}=\text{h}\rho(\text{g}+\text{a})$
Air pressure in the elevator $=\text{p}=\text{h}'\rho\text{g}$
Because the pressure is the same, h' > h.
$\therefore$ Air pressure > 76cm.

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 Fluid Mechanics→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

If a graph is plotted taking the temperature in Fahrenheit along $Y-$axis and the corresponding temperature in Celsius along the $X-$axis, it will be a straight line
→
A thin transparent sheet is placed in front of a Young's double slit. The fringe-width will:
→
In a thermodynamic process pressure of a fixed mass of a gas is changed in such a manner that the gas releases $20 \,J$ of heat when $8 \,J$ of work was done on the gas. If the initial internal energy of the gas was $30 \,J$, then the final internal energy will be ........ $J$
→
The pitch of an organ pipe is highest when the pipe is filled with
→
The acceleration due to gravity on a planet is same as that on earth and its radius is four times that of earth. What will be the value of escape velocity on that planet if it is ${v_e}$ on earth
→
Which of the following circular rods. (given radius $ r$ and length $l$ ) each made of the same material as whose ends are maintained at the same temperature will conduct most heat
→
A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Qare at distances of 2 m and 3 m respectively from the source. The ratio of the intensities of the waves at P and Q is:
→
The displacement of a particle after time $t$ is given by $x = \left( {k/{b^2}} \right)\left( {1 - {e^{ - bt}}} \right)$ where $b$ is a constant. What is the acceleration of the particle? 
→
Entropy of a thermodynamic system does not change when this system is used for
→
When an ideal diatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy of the gas, is
→