Physical group model questions discussion 12science

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12
Physics

Unit Three: Electricity and Magnetism

What do you mean by a shunt? Describe its use in converting a galvanometer into an ammeter. [2057]

What is drift velocity of an electron? Derive a relation between the current through a metallic conductor and the drift velocity in terms of the number of free electrons per unit volume of the conductor. [2059]

State and explain Ohm?s law. [2064]

What is potentiometer? Explain how do you compare emf of two cells using potentiontiometr. [2058]

What is a Wheatstone bridge? Obtain the balanced condition for the bridge. Explain how resistance can be measured by a meter bridge. [2068]

Explain, what do you mean by seebeck effect? How does thermoelectric emf vary with the temperature? [2057]

State and explain Faraday?s laws of electrolysis. Hence. Define Faraday?s constant. [2058]

Define the formula for the magnetic field at the centre of a circular coil carrying current. Explain why the magnetic field at the centre of the coil disappears when the circular coil is made infinitely large. [2059]

Derive an expression for the torque experienced by a current carrying rectangular coil placed in a uniform magnetic field and hence define magnetic dipole moment of the coil. [2060]

Derive an expression of force per unit length between two parallel conductors separated by a distance ?r? and carrying currents I1 and I2 in the same direction. [2066]

Define magnetic susceptibility and relative permeability and establish a relation between them. [2070 ?C?]

Obtain the expression for the emf induced in the conductor moving in a magnetic field. [2052]

State and explain Faraday?s law of electromagnetic induction. [2067]

An alternating e.m.f is applied across a capacitor. Show that the current in it leads to the applied e.m.f. by 90°.

12 Physics
Important questions

Unit Two: Physical Optics

State and explain Huygens?s principle to show that a plane wave front incident obliquely on a plane mirror is reflected as a plane wave front so that the angle of incidence is equal to the angle of reflection. [2060, 2068]

Define Michelson?s method to determine the speed of light. Write advantages of this method over Foucault?s method. [2067]

What are coherent source? Prove analytically that the bright and dark fringes in young?s double slit experiment are equally spaced. [2060]

Describe Young?s double slit interference experiment to determine the wavelength of the source of light. [2069]

What do you mean by polarization of light? Show that tan?p = np where ?p is the angle of polarization and ? is the refractive index of the transparent medium. [2059]

12 physics important
Long questions
Unit One: Wave and Optics

What are stationary waves? Derive an equation for such a wave. [2060]

What the principle of superposition is as applied to wave motion? Discuss the result of superposing two waves of equal amplitude and same frequency travelling in opposite direction. [2068]

How is a progressive wave different from a stationary wave? Derive a progressive wave equation. [2070 ?D?]

What is Newton?s formula for the velocity of sound? What correction was made by Laplace? [2053]

Describe the various modes of vibrations of the air column in an organ pipe. [2054]

What is Doppler?s effect? Derive an expression for the apparent frequency received by a stationary observer when a source is moving away from him. [2057]