A tank with a square base of an area of 1.0 m² is divided by a vertical partition in the middle. The bottom of the partition has a small-hinged door of area 20 cm². The tank is filled with water in one compartment, and an acid (of relative density 1.7) in the other, both to a height of 4.0 m. What is the force necessary to keep the door close?

1. 54.88 N
2. 56.0 N
3. 60.0 N
4. 45.5 N

During a blood transfusion, the needle is inserted in a vein where the gauge pressure is \(2000\) Pa. At what height must the blood container be placed so that blood may just enter the vein?
(The density of whole blood is \(1.06\times10^{3}\) kg/m³).
1. \(0.163\) m
2. \(0.192\) m
3. \(0.157\) m
4. \(0.754\) m

What is the largest average velocity of blood flowing in an artery of radius \(2\times 10^{-3}\) m if the flow must remain laminar?
(Take the viscosity of blood to be \(2.084\times 10^{-3}\) Pa-s and density of blood to be \(1.06\times 10^3\) kg/m³).
1. \(0.459\) m/s
2. \(0.0987\) m/s
3. \(0.983\) m/s
4. \(0.0897\) m/s

A plane is in level flight at a constant speed and each of its two wings has an area of 25 m². If the speed of the air is 180 km/h over the lower wing and 234 km/h over the upper wing surface, determine the plane’s mass. (Take air density to be 1 kg m^–3).

1. 6000 kg
2. 5400 kg
3. 4320 kg
4. 4400 kg

In Millikan’s oil drop experiment, what is the terminal speed of an uncharged drop of radius \(2\times10^{-5}\) m and density \(1.2\times10^{3}\) kg-m^–3? (Take the viscosity of air at the temperature of the experiment to be \(1.8\times10^{-5}\) Pa-s.)

Mercury has an angle of contact equal to 140° with soda-lime glass. A narrow tube of radius 1.00 mm made of this glass is dipped in a trough containing mercury. By what amount does the mercury dip down in the tube relative to the liquid surface outside? [The surface tension of mercury at the temperature of the experiment is 0.465 N m^–1. The density of mercury = 13.6 × 10³ kg m^–3.]

1. 4.21 mm
2. 5.34 mm
3. 3.12 mm
4. 6.16 mm

Two narrow bores of diameters \(3.0\) mm and \(6.0\) mm are joined together to form a U-tube open at both ends. If the U-tube contains water, what is the difference in its levels in the two limbs of the tube? (The surface tension of water at the temperature of the experiment is \(7.3\times 10^{-2}\) Nm^–1. Take the angle of contact to be zero and the density of water to be \(1.0\times 10^{3}.\) (\(g=9.8\) ms^–2)
1. \(4.95\) mm
2. \(3.73\) mm
3. \(8.91\) mm
4. \(5.36\) mm

The term 'fluid' is used for 

1. Liquids only

2. Gases only

3. A mixture of liquid and gas only

4. Both liquids and gases

Select wrong statement about pressure

1. Pressure is a scalar quantity

2. Pressure is always compressive in nature

3. Pressure at a point is same in all directions

4. None of these

Gauge pressure

1. May be positive

2. May be negative

3. May be zero

4. All of these