# Pascal's Law

## Trending Questions

**Q.**The three vessels shown in figure have same base area. Equal volumes of a liquid are poured into the three vessels. The force on the base will be

- Maximum in vessel A
- Maximum in vessel B
- Maximum in vessel C
- Equal in all the vessels

**Q.**If pressure at half depth of a lake is equal to 23rd pressure at the bottom of the lake, then what is the depth of the lake?

(Take atmospheric pressure as 105 Pa, density of water as 1000 kg/m3 and g=10 m/s2)

- 6.67 m
- 60 m
- 20 m
- 10 m

**Q.**

A hydraulic automobile lift is designed to lift cars with a maximum mass of 3000 kg. The area of cross-section of the piston carrying the load is 425cm2 . What maximum pressure would the smaller piston have to bear?

**Q.**In a car lift, compressed air exerts a force F1 on a small piston having a radius of 5.0 cm. This pressure is transmitted to the second piston of radius 10.0 cm. If the mass of the car to be lifted by the second piston is 1350 kg, calculate F1 [Take g=10 m/s2]

- 1800 N
- 3375 N
- 5625 N
- 2400 N

**Q.**

What are the methods of measuring surface tension?

**Q.**The pressure at the bottom of a tank of water is 3P where P is the atmospheric pressure. If the water is drawn out till the level of water is lowered by one-fifth, the pressure at the bottom of the tank will now be:

- 85P
- 45P
- 2P
- 135P

**Q.**In a hydraulic jack as shown, mass of the car is W=800 kg, A1=10 cm2, A2=10 m2. The minimum force F required to lift the car is: [Take g=10 m/s2]

- 1 N
- 0.8 N
- 8 N
- 16 N

**Q.**A uniformly tapering vessel is filled with a liquid of density 900 kg/m3. The force that acts on the base of the vessel due to the liquid (excluding atmospheric force) is : [Take g=10 m/s2]

- 3.6 N
- 7.2 N
- 9.0 N
- 12.6 N

**Q.**

A stone of mass 2kg is tied to a string of length 0.5m. If the breaking tension of the string is 900N, then the maximum angular velocity, the stone can have in uniform circular motion is:

20 rad/s

10 rad/s

40 rad/s

30 rad/s

**Q.**

What are the three steps of scientific method?

**Q.**An air bubble of radius 1 cm in water has an upward acceleration 9.8 cm/s2. The density of water is 1 g/cm3 and water offers negligible drag force on the bubble. The mass of the bubble is (g=980 cm/s2)

- 4.51 gm
- 3.15 gm
- 4.15 gm
- 1.52 gm

**Q.**A piston of cross-sectional area 100 cm2 is used in a hydraulic pump to exert a force of 107 dyne on the water. The cross-sectional area of the other piston which supports a truck of mass 2000 kg is

- 9.8×102 cm2
- 9.8×103 cm2
- 1.96×103 cm2
- 1.96×104 cm2

**Q.**Consider a solid sphere of radius R and mass density ρ(r)=ρ0(1−r2R2), 0<r≤R. The minimum density of a liquid in which it will float is:

- ρ03
- ρ05
- 2ρ05
- 2ρ03

**Q.**

What is the dimensional formula of pressure difference?

**Q.**There is a circular tube in a vertical plane. Two liquids which do not mix and of densities d1 and d2 are filled in the tube. Each liquid subtends 90∘ angle at centre. Radius joining their interface makes an angle α with vertical.

Ratio d1d2 is:

- 1+tan α1−tan α
- 1+sin α1−cos α
- 1+sin α1−sin α
- 1+cos α1−cos α

**Q.**To lift an automobile of 5000 kg, a hydraulic lift with a large piston 800 cm2 in area is employed. Calculate the force that must be applied to a small piston of area 5 cm2 to achieve it.

- 612.5 N
- 306.25 N
- 153.12 N
- 408.56 N

**Q.**Find the depth of a lake( in km ) at which the density of water is 1% greater than at the surface, if compressibility of water is 50×10−6/atm

**Q.**

$Newton-meter$ is the SI unit of

Thrust

Pressure

Torque

Work

**Q.**In a hydraulic lift, compressed air exerts a force F1 on a small piston having a radius of 5 cm. This pressure is transmitted to a second piston of radius 15 cm. If the mass of the load to be lifted is 1350 kg, calculate the pressure acting on the smaller piston.

[Take g=10 m/s2]

- 3×105 Pa
- 2×105 Pa
- 1.9 Pa
- 1.9×105 Pa

**Q.**The apparent depth of water in a cylindrical water tank of diameter 2R cm is reducing at the rate of x cm/min when water is being drained out at a constant rate. The actual amount of water drained in cm3/min is

(n1= refractive index of air, n2= refractive index of water)

- xπR2n1n2
- xπR2n2n1
- 2πRn1n2
- πR2x

**Q.**The force acting on a window of area 50 cm×50 cm of a submarine at a depth of 2000 m in an ocean, interior of which is maintained at sea level atmospheric pressure is

(Density of sea water =103 kg/m3, g=10 m/s2 )

- 106 N
- 25×106 N
- 5×105 N
- 5×106 N

**Q.**

Find the force exerted by the water on a 2 m2 plane surface of a large stone placed at the bottom of a sea 500 m deep. Does the force depend on the orientation of the surface ?

**Q.**A tube 1 cm2 in cross section is attached to the top of a vessel 1 cm high and of cross section 100 cm2. Water is poured into the system filling it upto a height of 100 cm above the bottom of the vessel as shown in the figure. Take g=10 m/s2. Find the correct statement. Take atmospheric pressure P0=105 bar.

- The weight of water in the system is 1.99 N.
- Both (a) and (b) are correct.
- Neither (a) nor (b) is correct.
- The force exerted by the water against the bottom of the vessel is 1100 N.

**Q.**

The action of paint gun is based on:

**Q.**

A steel blade float on the surface of pure water when detergent is added, it sinks.why?

**Q.**

Kerosene oil rises up in the wick of a lantern because of:

The gravitational pull of the wick

Buoyant force of air

Surface tension

Diffusion of the oil through the wick

**Q.**A plate of mass 10 gm is in equilibrium in air due to the force exerted by light beam on plate. Calculate power of the beam. Assume plate is perfectly absorbing.

- 3×107W
- 2×107W
- 3×105W
- 2×105W

**Q.**A hydraulic automobile lift is designed to lift cars with a maximum mass of 300 kg. The area of cross-section of the piston carrying the load is 500 cm2. What maximum pressure would smaller piston have to bear?

- 5.88×104 Pa
- 8.55×104 Pa
- 2.94×104 Pa
- 11.66×104 Pa

**Q.**

A cylindrical tank of height 0.4 m is open at the top and has a diameter of 0.16 m. It is filled with water upto a height of 0.16 m. Find the time taken to empty the tank through a hole of radius 5 x 10^{-3} m in its bottom.

t = 23.5 s

t = 47.3 s

t = 19.02 s

t = 46.26 s

**Q.**

Consider the situation in figure. The bottom of the pot is a reflecting plane mirror, S is a small fish and T is human eye. Refractive index of water is μ.

(a) At what distance(s) from itself will the fish see the image(s) of the eye ?

(b) At what distance(s) from itself will the eye see the image(s) of the fish.