A uniform narrow tube of length one metre with one end closed contains 25 cm long mercury thread, which traps a column of air at the closed end. When the tube is held vertically with the open end up, the length of the air column near the closed end is 21 cm and when the tube is held horizontally, the length of the air column near the closed end is ‘L’. If the atmospheric pressure is equal to the pressure of 75 cm of mercury, then \( L \) is:
Show Hint
- \( 35 \, \text{cm} \)
- \( 28 \, \text{cm} \)
- \( 7 \, \text{cm} \)
- \( 14 \, \text{cm} \)
The Correct Option is B
Solution and Explanation
Step 1: The pressure at the closed end of the tube is given by: \[ P = \text{atmospheric pressure} + \text{pressure due to mercury column} \]
Step 2: When the tube is held vertically, the pressure at the closed end is \( 75 \, \text{cm} \) of mercury.
Step 3: When the tube is held horizontally, the length of the air column changes due to the balance of pressures. The total length of the column is \( L = 28 \, \text{cm} \).
Top TS EAMCET Physics Questions
- A wooden box lying at rest on an inclined surface of a wet wood is held at static equilibrium by a constant force $F$ applied perpendicular to the incline. If the mass of the box is $1\,kg$, the angle of inclination is $30^{\circ}$ and the coefficient of static friction between the box and the inclined plane is $0.2$, the minimum magnitude of $\vec{F}$ is (Use $ g = 10\,m/s^2$)
- A metre scale made of steel reads accurately at $25^{\circ} C$ . Suppose in an experiment an accuracy of $0.06\, mm$ in $1\,m$ is required, the range of temperature in which the experiment can be performed with this metre scale is (coefficient of linear expansion of steel is $ 11 \times 10^{-6} /^{\circ} \, C$ )
- Consider a solenoid carrying current supplied by a DC source with a constant emf containing iron core inside it. When the core is pulled out of the solenoid, the change in current will
- A parallel beam of light of intensity \(I_0\) is incident on a coated glass plate. If \(25\%\) of the incident light is reflected from the upper surface and \(50\%\) of light is reflected from the lower surface of the glass plate, the ratio of maximum to minimum intensity in the interference region of the reflected light is
- A thermocol box has a total wall area (including the lid) of $1.0 m ^{2}$ and wall thickness of $3 cm$. It is filled with ice at $0^{\circ} C$. If the average temperature outside the box is $30^{\circ} C$ throughout the day, the amount of ice that melts in one day is [Use $K_{\text {thermocol }}=0.03 W / mK$ $.L_{\text {fusion (ice) }}=3.00 \times 10^{5} J / kg ]$
Top TS EAMCET Fluid Mechanics Questions
A cylindrical vessel, open at the top, contains 15 liters of water. Water drains out through a small opening at the bottom. 5 liters of water comes out in time t1, the next 5 litre in further time t2, and the last 5 litre in further time t3. then:
A cylinder of mass m and material density ρ hanging from a string is lowered into a vessel of cross - sectional area A containing a liquid of density σ (< ρ) until it is fully immersed. The increase in pressure at the bottom of the vessel is:
- An incompressible fluid is flowing through a tube of uniform cross-section. The increase in the power of the pump required to double the rate of flow is:
- Two spherical rain drops of radii in the ratio 4:5 are falling vertically through air. The ratio of the terminal velocities of the rain drops is:
A big liquid drop splits into 'n' similar small drops under isothermal conditions, then in this process:
Top TS EAMCET Questions
- A bag contains $5$ red balls, $3$ black balls and $4$ white balls are drawn at random. The probability that they are not of same colour is
- If $cosec\, \theta - \cot \theta = 2017$, then quadrant in which $\theta $ lies is
- If $a$ is a unit vector, then $| a \times \hat{ i }|^{2}+| a \times \hat{ j }|^{2}+| a \times \hat{ k }|^{2}=$
- $A$ straight line makes an intercept on the $Y$-axis twice as long as that on $X$-axis and is at a unit distance from the origin. Then the line is represented by the equations
- Let $S$ and $S'$ be the foci of an ellipse and B be one end of its minor axis. If $SBS'$ is an isosceles right angled triangle then the eccentricity of the ellipse is