Assertion: Use of ball bearings between two moving parts of a machine is a common practice. 

Reason:  Ball bearings reduce vibrations and provide good stability.

• If both assertion and reason are true and reason is the correct explanation of the assertion

• If both assertion and reason are true but reason is not the correct explanation of the assertion

• If assertion is true, but reason is false

• Both assertion and reason are false statements

Assertion: A thin stainless steel needle can lay floating on a still water surface. 

Reason:  Any object floats when the buoyancy force balances the weight of the object.

• If both assertion and reason are true and reason is the correct explanation of the assertion

• If both assertion and reason are true but reason is not the correct explanation of the assertion

• If assertion is true, but reason is false

• Both assertion and reason are false statements

A candle of diameter d is floating on a liquid in a cylindrical container of diameter D ( D >> d ) as shown in figure. If it is burning at the rate of 2 cm/hour then the top of the candle will

• remain at the same height

• fall at the rate of 1 cm/hour

• fall at the rate of 2 cm/hour

• go up at the rate of 1 cm/hour

64.

A given shaped glass tube having uniform cross section is filled with water and is mounted on a rotatable shaft as shown in figure. If the tube is rotated with a constant angular velocity  ω when

• water levels in both sections A and B go up

• water level in section A goes up and that in B comes down

• water level in section A comes down and that in B it goes up

• water levels remain same in both sections

Assertion:  Specific gravity of a fluid is a dimensionless quantity

Reason: : It is the ratio of density of fluid to the density of water.

• If both assertion and reason are true and reason is the correct explanation of assertion 

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion: For Reynold number R_e > 2000, the flow of fluid is turbulent. 

Reason: Inertial forces are dominant compared to the
viscous forces at such high Reynold numbers.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

A sphere of mass Mand radius R is falling in a viscous fluid. The terminal velocity attained by the falling object will be proportional to

• R²

• R

• 1/R

• 1/R²

The old age arteries carrying blood in the human body become barrow resulting in an increase in blood pressure. This follows from

• Pascal's law

• Stoke's law

• Bernoulli's principle

• Archimedes principle

Assertion: Smaller drops of liquid resist deforming forces better than the larger drops. 

Reason: Excess pressure inside a drop is directly proportional to its surface area

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If assertion is true but reason is false

Bernoulli's equation is a consequence of conservation of

• energy

• linear momentum

• angular momentum

• mass