Solve your IGNOU Doubts

Question:

b) Define solubility product constant and derive the relationships between solubility and solubility product constants for salts of AB2, A2B types.

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Question:

a) Explain the effect of common ions on the ionisation equilibria of weak acids with the help of a suitable example.

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Question:

b) Define degree of ionisation of a weak electrolyte and discuss the factors affecting it.

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Question:

a) In the following equilibrium, predict the direction of shift of equilibrium for each condition listed below:

$N_{2}(g) + 3H_{2}(g) \leftrightharpoons 2NH_{3}(g) + 92 kJ$

i) Addition of $H_{2}$

ii) increased pressure

iii) lowering of temperature.

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Question:

b) What is reaction quotient and how is it helpful in determining the direction of a given reaction?

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Question:

a) Give the statements of Zeroth, First, Second and the Third laws of thermodynamics and outline their significance.

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Question:

b) Differentiate between enthalpy driven and entropy driven reactions with the help of suitable examples.

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Question:

a) Define standard enthalpy of formation and describe a method for its direct determination with the help of an example.

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Question:

a) Define and explain a thermodynamically reversible process.

b) 0.25 mol of an ideal monoatomic gas undergoes isothermal expansion from a volume of 2.0 dm3 to 10 dm3 at 27 oC. Calculate the maximum work that can be obtained from this process.

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Question:

e) i) Show that only odd harmonics can be generated in a closed-end organ pipe.

ii) Determine the fundamental frequency and the first 3 overtones of an organ pipe

of length 1.7 m and closed at one end. Take the speed of sound to be 340 $ms^{-1}.$

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Question:

d) Standing waves are produced by superposition of the following waves: $y_{1}(x,t)=0.2sin \pi (t-2x)$ and

$y_{2}(x,t)=0.2sin \pi (t+2x)$

(i) Obtain the resultant displacement of the particle at x at time t. (ii) For what value of x will the displacement be zero at all times? (iii) What is the distance between two nearest values of x at which displacements are zero? Is this distance related to the wavelength of the standing wave?

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Question:

c) i) The equation of transverse wave on a string is given by $y=5sin \pi (4.0t-0.02x)$

where y and x are in cm and t is in second. Calculate the maximum speed of a particle on the string and wavelength of the wave.

ii) The linear density of a vibrating string is $1.3\times 10^{-4}kg m^{-1}.$ A transverse wave is propagating on the string and is described by the equation: $y(x,t)=0.021$ sin $(x+30t)$

where x and y are in meters and t is in seconds. Calculate the tension in the string.

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Question:

a) Calculate the volume of the tetrahedron whose vertices are the points A = (3, 2, 1), B = (1, 2, 4), C = (4, 0, 3) and D = (1, 1, 7).

b) For three vectors $\left ( \vec{u}\times \vec{v} \right )\left [ \left ( \vec{v}\times \vec{w} \right ) \times \left ( \vec{w} \times \vec{u}\right )\right ]=\left [ \vec{u.}\left ( \vec{v}\times \vec{w} \right ) \right ]^{2}.$

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Question:

ii) A train moving with speed 72 km $h^{-1}$ emits a whistle of frequency 500 Hz. A person is standing stationary on the platform. Calculate the frequency heard by the person if the train (i) approaches and (ii) recedes away from the listener

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Question:

i) A sound wave of frequency 400 Hz travels in air at a speed of 320 $ms^{-1}$ Calculate the phase difference between two points on the wave separated by a distance of 0.2 m along the direction of travel of the wave.

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Question:

a) A Transverse waves propagating on a stretched string encounter another string of different characteristic impedance. (i) Write down the equations of particle displacement due to the incident, reflected and transmitted waves. (ii) Specify the boundary conditions and (iii) use these to obtain expressions for reflection and

transmission amplitude coefficients.

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Question:

Consider N identical masses connected through identical springs of force constant k. The free ends of the coupled system are rigidly fixed at $x=0$ and $x=l.$ The masses are made to execute longitudinal oscillations on a frictionless table.

i) Depict the equilibrium as well as instantaneous configurations.

ii) Write down their equations of motion, decouple them and obtain frequencies of normal modes.

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Question:

d) A body of mass 0.2 kg is suspended from a spring of force constant 80 $Nm^{-1}.$ A

damping force is acting on the system for which γ = 4 Nsm−1. Write down the equation of motion of the system and calculate the period of its oscillations. Now a harmonic force F =10cos10t is applied. Calculate a and θ when the steady state

response is given by a cos(ωt − θ).

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Question:

c) Establish the equation of motion of a damped oscillator. Solve it for a weakly damped oscillator and discuss the significance of the results.

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Question:

b) Consider a particle undergoing simple harmonic motion. The velocity of the particle at position $x_{1}$ is $v_{1}$ and velocity of the particle at position $x^{2}$ is $v_{2}.$ Show that the ratio of time period (T) and amplitude (A) is: