i. Heat needed to raise the temperature of 8gm of hydrogen from 10⁰C to 15⁰C at constant pressure \(=nC_p∆θ=\frac{m}{M}C_p∆θ\) \(=\frac{8}{2}×28.8(15-10) \) = 576 J  .....

Initial volume (V1) = V (Say) Initial temperature (T1) = 10⁰C = (273 + 10) = 283 K Final temperature (T2) = ? We have, \(T_1V_1=T_2V_2^{r-1} \) .....

Derivation for an expression for the work done by an ideal gas during isothermal expansion. Consider a mole of ideal gas contained in a cylinder fitted with a frictionless piston. Let P1 and V1 be the initial pressure and initial volume of the gas .....

In practice, there are four different thermodynamic processes. a. Isothermal process: In an isothermal system, the temperature remains constant but the pressure and volume of the system may change. When a gas is expanded isothermally, the supplied .....

First part: Adiabatic expansion is the process in which total heat remains constant but temperature pressure and volume of the system may change. In this expanison, the gas (in system) is enclosed (placed) in a non-conducting (insulating) vessel. .....

Consider one mole of an ideal gas enclosed in a cylinder fitted with a frictionless piston. If the gas is heated at a constant volume such that its temperature rises by dT, heat supplied (dQ) = 1 × Cv × dT where Cv is sp heat .....

An expansion or conraction of  a gas in which no heat enters or leaves the gas is called an adiabaic expansion or contraction. A reversible adiabatic change is an adiabatic change that can be retracted in the opposite direction so that it .....

There is no relative motion between the cylinder filled with gas and the fast-moving train as the cylinder is kept inside it. So, the amplitude of vibration of gas molecules doesn't alter and the internal energy of the gas doesn't change. .....

The temperature of a body can be increased in two ways: (i) by heating the body and (ii) by doing works on it. During adiabatic compression of a system, no heat is supplied to it but its temperature increases due to external work done on the system. .....

Work done by a system is numerically equal to the area under the P-V diagram. In the figure, the area under the P-V diagram for path 1 is maximum and that for path 3 is the minimum among three paths. Therefore, the work done by the system is the .....

Air escaping from an air-hose flows from high pressure to low pressure (i.e. atmosphere pressure). As the air escaping is sudden, the process is adiabatic. We have the relation, \(TP\frac{1-γ}{γ}=constant \) .....

Yes, at absolute zero, molecules are supposed to be at rest and hence they possess only potential energy due to intermolecular forces between them. In this case, the internal energy is only due to their random motion and potential energy due to .....

According to the first law of thermodynamics, dQ = dU + dW For an adiabatic process, dQ = 0 During expansion, the change in volume (dV) of the gas is positive and hence dW is also positive. This implies that work is done by the gas. The gas does .....

Adiabatic expansion is the process in which total heat remains constant but temeprature pressure and volume of the system may change. In this expansion, the gas (in system) is enclosed (placed) in a non-conducting (insulating) vessel. Therefore, the .....

Internal energy is the sum of internal potential energy and internal kinetic energy. In an ideal gas, there is no intermolecular attraction and hence it does not possess P.E. i.e. the internal energy is totally kinetic in nature and is a function of .....

Consider a gas enclosed in a cylinder fitted with a piston. If the piston is suddenly pushed in, the temperature of the gas rises, although no heat is supplied to it, only work is on it. ∵ Specific heat = Heat energy suplied (∆Q)/mass .....

i) Isothermal expanison: In an isothermal system, the temperature remains constant but the pressure and volume of the system may change. When a gas is expanded, the supplied heat is equivalent to mechanical work or external work. Since temperature .....

When heat is added to an ideal gas at constant volume, all the heat goes into raising the temperature that is internal energy of ideal gas is wholly kinetic in nature. But when heat is added to the non ideal substance at constant volume, the .....

When gas is heated at constant volume, no work is done. The whole heat supplied to the gas is used to increase the internal energy only. When a gas is heated at constant pressure, the supplied heat is used: i. To increase internal energy, and ii. To .....

When gas is heated at a constant volume, now work is done. The whole heat supplied to the gas is used to increase the internal energy only. When a gas is heated at constant pressure, the supplied heat is used: i. To increase internal energy, and ii. .....

Suppose a small sphere of radius r and density D are released from the bottom of a column of liquid of density (P > D). The following three forces act on the sphere moving upward: i. Weight 'W' of the sphere acting vertically downward .....

The total energy (kinetic energy + potential energy + pressure energy) per unit mass of incompressible and non-viscous liquid flowing through a pipe of non-uniform cross-section remains constant. \(i.e.\frac{E}{M}=constant .....

Terminal velocity of a body is defined as the constant maximum velocity acquired by the body while moving through a viscous medium. The body attains terminal velocity when its weight becomes equal to the sum of the upward viscous force and the .....

Relation between surface tension and surface energy As shown in the figure, PQRS is a rectangular frame of wire in which the portion PQ of length l is movable. When it is dipped in a soap solution, a flim is formed on it. This flim pulls the portion .....

The phenomenon of the rise or fall of liquid inside a capillary tube is called capillarity. A blotting paper soaks ink, oil rises up a lamp wick by capillary action. Let a capillary tube of internal radius r be held vertically in water which has a .....

Here, Coefficient of viscosity (η) = 2.42 Nsm-2 Radius of steel ball (r) = 2.0 mm = 2.0 × 10-3 m Density of steel (ρs) = 7800 kgm-3 Density of castor oil (ρc) = 940 kgm-3 When the ball falls with terminal velocity, .....

Radius (r) = 1 mm = 1 × 10-3 m η = 0.2 Nsm-2 ρair = 1.29 kgm-3 Sp. gravity of oil = density of oil = 0.9 gm-3 or, σoil = 0.9 × 103 kgm-3 v = ? \(∴v=\frac{2}{9}\frac{r^2g(ρ-σ)}{η} .....

Let V and v be the terminal velocity of larger and small drops and R and r be their respective radius. Viscous force for the smaller drop, F = 6πηrv Weight of each drop, W = mg =  ρ × v × g .....

Area (a) = 55 m2 v2 = 155 m/s v1 = 140 m/s From Bernoulli's principle, \(\frac{P_1}{ρ}+\frac{1}{2}v^2_1=\frac{P_2}{ρ}+\frac{1}{2}v^2_2 \) \(or, P_1+\frac{1}{2}ρv^2_1 = .....

To calculate the work done, we have to determine the increase in the surface area. Let D be the diameter of the big drop and 'd' be that of each small drop. Surface area of big drop = πD2 Volume of big drop =  .....

Given, Original radius (R) = 5 × 10-3 m No. of drops = 8 Surface tension = 0.72 N/m Since No. of drops = original volume/final volume of each drop \(or, 8 = \frac{\frac{4}{3}πR^3}{\frac{4}{3}πr^3} \) .....

Here given, Length of plate (l) = 6 cm = 0.06 m Breadth of plate (b) = 4 cm = 0.04 m Thickness of plate (t) = 2 mm = 2 × 10-3 m If the plate is placed vertically, with its largest side just touching water, then total length of contact is .....

Here, diameter of capillary tube (d) = 0.40 mm = 0.4 × 10-3 m Radius (r) = 0.2 × 10-3. Density of liquid (ρ) = 800 kgm-3 Surface Tension (T) = 5.0 × 10-2 Nm-1 Angle of contact (θ) = 30⁰ Height of the .....

Here, Angle of contact (θ) = 135⁰ Diameter (d) = 2 mm Surface tension (T) = 0.547 Nm-1 We know, \(T=\frac{rρgh}{2cosθ} \) .....

Maximum load that a boy can lift = 150 N water i.e. Maximum load that he can lift = 150 N mercury i.e wt. of mercury = 150 N or, mg = 150 or, ρ × v × g = 150 \(or, v = .....

Mass of woman, m = 45 kg Density of ice, ρi = 920 kgm-3 Let V be the volume of water displaced The buoyancy force exerted by water = V ρwg According to the principle of floatation Weight of woman + weight of ice block = Buoyant .....

Consider a sphere of radius r and density ρ falling under gravity in a fluid a density ρ. The following three forces act on the falling sphere: i. Weight W of the sphere acting vertically downwards through the C.G. of the .....

A maximum load that a boy can lift = 250 N of water i.e Maximum load that he can lifet = 250 N of mercury (considering he can lift equal load) i.e weigh of frequency = 250 N or, mg = 250 N or, V × ρ × g = 250 N or, .....

Stoke's law: This viscous force F acting on a small sphere of radius r, when it falls through a viscous fluid, depends upon (i) coefficient of viscosity (η) of the fluid (ii) velocity (v) of the sphere and (iii) radius (r). It is given by, F .....

According to Bernoulli's principle, in fluid flow, the pressure is maximum where the velocity is the minimum and vice-versa. The breeze blowing over the chimney creates low pressure there than the pressure insidethe chimney. So, the smoke rises .....

During certain windstorms, the wind blows the roof because outside the roof reduces according to Bernoulli's theoem. But, pressure remains the same as atmospheric pressure inside the roof. Due to this difference in pressure, the light roofs are .....

A lubricating oil is usually used in the moving parts of the machine to reduce friction In cold days, the viscosity of oil increases due to the decrease in temperature. This causes the various parts of the machine to .....

Viscosity is the property of fluid (liquid or gas) by virtue of which it opposes the relative motion between its different layers. Higher the value of coefficient of viscosity of a liquid, more viscous the liquid is. That is, more external force is .....

From the definition \(η=\frac{F}{A\frac{dv}{dx}} \) \(∴\frac{dv}{dx}=\frac{F}{Aη}\)      \([∵\frac{dv}{dx}velocity gradient] .....

The atmospheric pressure is low at high elevations. So, according to Bernoulli's principle, the pressure difference on the sides of the wings to uplift the plane is low. For longer runways, a large pressure difference in the aerofoils is created .....

Consider a liquid flowing steadily over a fixed horizontal surface. It flows in the form of layers. When liquid moves, these layers slide over each other. A layer in contact with the solid surface is practically stationary, but the farthest layer, .....

When a fast-moving train passes from the platform, the air between the person and train acquires high velocity and hence low pressure according to Bernoulli's theorem. Due to this difference in pressure, a force is produced which may push anyone .....

Due to the irregular shape of the camphor, it may dissolve more at one end than at the other end in water. Thus, the surface tension of water will decrease by an unequal amount at the various ends of the piece of camphor. It produces a resultant .....

The rise of liquid in a capillary tube is given by: \(h=\frac{2Tcosθ}{ρgr} .......(i) \) Let C be the centre of curvature of the liquid meniscus and R be the radius of curvature of the meniscus. In the right angled .....

In the case of small drops of mercury, the gravitational potential energy is negligable in comparison to the potential energy due to surface tension. Consequently, to keep the drop in equilibrium, the mercury drop surface tends to contract so that .....