Question 1 :
Find the lifting force of a 4 kg cork lifebelt in sea water if the densities of cork and sea water are $ 0.2\times 10^3\,kg/m^3$ and $1.03\times 10^3\,kg/m^3$ respectively.

Question 2 :
It is better to use a sharp tipped nail than a blunt nail because :

Question 3 :
State whether true or false:A sheet of paper falls slower than one that is crumpled into a ball.

Question 4 :
The fluid itself exerts pressure whose force component is equal to its ___________. Complete the sentence.<br/>

Question 5 :
Assertion: The force exerted by the fluid is due to the collisions of molecules with their surroundings. Reason: The normal force exerted by the fluid particles on the walls of the container results pressure.

Question 6 :
A glass bulb is balanced by a brass weight in a sensitive beam balance. Now the balance is covered by a glass-jar which is then evacuated. Then:<br/>

Question 8 :
There are two round tables in the physics classroom: one with the radius of $50\ cm$, the other with a radius of $150\ cm$. What is the relationship between the two forces applied on the tabletops by the atmospheric pressure? then value of $\dfrac{F_1 }{F_2} $ is:

Question 9 :
What is a pressure on the smaller piston if both the pistons are at same horizontal level? (Take $g=10m$ ${s}^{-2}$)

Question 10 :
Which of the following is not caused due to noise pollution?

Question 11 :
<p>Which of the following frequency of sound can be heard by a dog but not by a man?</p>

Question 13 :
A transverse wave of frequency 50 Hz is reflected from a wall. 50% of the energy of the wave is lost at the wall. The frequency of the reflected wave will be

Question 16 :
When a sound wave enters the ear, it sets the eardrum into oscillation, which &#160;in turn causes oscillation of 3 tiny bones in the middle ear called ossicles. This oscillation is finally transmitted to the fluid filled in inner portion of the ear termed as inner ear, the motion of the fluid disturbs hair calls within the inner ear which transmit nerve impulses to the brain with information that a sound is present. The three bones present in the middle ear are named as hammer, anvil and stirrup. Out of these the stirrup is the smallest one and this only connects the middle &#160;ear to inner ear as shown in the figure below. The area of stirrup&#160;and its extent of connection with the inner ear limits the sensitivity of the human ear. Consider a person's eat whose moving part of the eardrum has an area of about 43 mm$^{2}$ and the area of stirrup is about 3.2 mm$^{2}$. The mass of ossicles is negligible. As a result, force&#160;&#160;exerted by sound wave in air on eardrum and ossicles is same as the force exerted by ossicles on the inner ear. Consider a sound wave having maximum pressure fluctuation of $3\times10^{-2}$&#160;Pa from its normal equilibrium pressure value which is wqual to $10^{5}$ Pa. Frequency of sound wave is 1200 Hz.&#160;<br/>Data: Velocity of sound wave in air is &#160;332 m/s. Velocity of sound wave in fluid (present in inner ear) is 1500 m/s. Bulk modulus of air is $1.42\times10^{5}$ Pa. Bulk modulus of fluid is $2.18\times10^{9}$ Pa.<br/><br/><br/>Find the pressure amplitude of given sound wave in the fluid of inner ear.&#160;