PHYSICS [2 Mark Question Answer]

Principle of Archimedes' states that when a body is totally or partially immersed in a fluid, it experiences an upthrust equal to the weight of the fluid displaced. Yes, it applies to gases also.

The bottom of the hydrometer is made heavier by loading it with lead shots so that it floats vertically with some of its portion outside the surface of the water in the jar.

The density of egg is greater than fresh water so it sinks in fresh water but due to the addition of salt density of water increases which makes the density of salt water greater than egg and hence floats in a strong solution of salt.

Density of iron is less than the density of mercury; hence, an iron nail floats in mercury and density of iron is more than the density of water; hence, an iron nail sinks in water.

We don't feel uneasy even under enormous pressure of the atmosphere above us because our blood also exerts a pressure called blood pressure, which is greater than atmospheric pressure. So, there is balance between our blood pressure and atmospheric pressure.

Factors which affect the atmospheric pressure as we go up are:
(i) Weight of gaseous column.
(ii) Density of gaseous column.

A atmospheric pressure diving suit is a garment or device designed to protect a diver from the underwater environment. Yes, diving suits create buoyancy.

All liquid exerts a upward force on the body placed in it. This Phenomenon is called buoyancy.

Atmospheric point at any point in the air at rest is equal to the weight of a vertical column of air on a unit area surrounding the point, the column extending to the top of the atmosphere.

(i) A hydraulic press can be used for extracting the juice of sugarcane, sugar beet, etc.
(ii) A hydraulic press can be used for pressing cotton bales, quilts, books, etc.

When a block of cork is immersed in water buoyant force acts on it in an upward direction so to overcome this force we have to apply an equal force in a downward direction to keep a block of cork inside water.

Relative density = density of substance/density of water at 4°C.
As the relative density of platinum is 21.50, this means platinum is 21.5 times denser than water at 4°C.

Relative density of wax = 0.95
Relative density of brine = 1.1
(Density of wax/ Density of brine) = fraction submerged
0.95/1.1 = fraction of volume submerged
Fraction of volume submerged = 0.86

When a floating piece of ice melts into water, it contracts by the volume equal to the volume of ice pieces above the water surface while floating on it. Hence, the level of water does not change when ice floating on it melts.

All liquid exerts an upward force on the body placed in it. This Phenomenon is called buoyancy.

Density of iron is less than the density of mercury; hence, an iron nail floats in mercury and density of iron is more than the density of water; hence, an iron nail sinks in water.

The density of iron is less than the density of mercury so it will float on the surface of the mercury. The apparent weight of the floating iron ball is zero.

Mercury is used in barometer because
(i) It can be obtained in pure form.
(ii) It does not vaporizeat ordinary temperatures.
(iii) Its density is high and hence the length of the mercury column supported by atmospheric pressure is 76 cm which is practically possible.

A barometer is a device which is used for measuring atmospheric pressure. Barometers are used in weather forecasting and in measuring altitudes.

A hydraulic press works on the principle of pascal's law. A hydraulic press can be used for extracting the juice of sugarcane, sugar beet, etc.

There are five main types of ambient pressure suits. These are wetsuits, drysuits, semidry suits, dive skins, etc.

When the diver moves horizontally the depth from the surface remains the same and as we know that pressure at depth h is given by P = h × p × g so as depth remains the same pressure would remain the same while moving horizontally. (Density of liquid, g also remains the same).

A fluid exerts pressure on the bottom due to its weight and on the walls of the container in which it is enclosed by virtue of its ability to flow. This is called fluid pressure.

Thrust is the force applied on a surface in a perpendicular direction and it is a vector quantity. The effect of thrust per unit area is pressure, and it is a scalar quantity.