IFS (Forests Services) Physics (Mains): Questions 22 - 27 of 34

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Question number: 22

» Electronics » Op-Amps, FET, JFET and MOSFET

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Appeared in Year: 2011

Essay Question▾

Describe in Detail

Explain the basic structure and operation of an channel FET.

How FET acts as an amplifier? Explain.

Explanation

  • The FET have three terminals: Source , Gate and Drain . The FET controls the flow of current from source to drain by applying voltage across the gate and source terminals. Therefore, this device is also called voltage controlled devices.

  • FETs are composed of PN-junction or Schottky junction, theref

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Question number: 23

» Particle Physics & Solid State Physics » Particle Physics » Quark Structure of Hadrons

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Appeared in Year: 2011

Essay Question▾

Describe in Detail

What are quarks? Give any four properties. Give quark composition of the following particles:

Explanation

  • Quark is one of the fundamental particles in physics. From the combination of these quarks, hadrons are formed, like proton and neutrons are formed by the quarks.

  • The anti – particle of a quark is the anti – quark. Quark and anti – quark are only two fundamental particles, which interact through all four fundamental forces of physics: Gravi

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Question number: 24

» Molecular Physics » Molecular Hydrogen in Astronomy Fluorescence and Phosphorescence

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Appeared in Year: 2011

Essay Question▾

Describe in Detail

What is the mechanism of emission of light on fluorescent lamps and in painted signboards?

Explanation

Construction of A Fluorescent Lamp in figure

Construction of a Fluorescent Lamp in Figure

In figure construction of a fluorescent lamp is shown.

  • A fluorescent lamp is containing liquid mercury and argon (or xenon) or krypton in a glass tube. This glass tube is coated with a fluorescent, which is made of varying blends of metallic and phosphor powder.

  • At the end of the tube, there i

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Question number: 25

» Physical Optics » Polarisation and Modern Optics » Ruby and He-Ne Lasers

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Appeared in Year: 2013

Essay Question▾

Describe in Detail

Explain the lasing action of laser using energy level diagram and describe the operation of laser experimental setup. (Section A)

Explanation

  • The light is produced in He – Ne laser by atomic transitions in the Neon atom. The Helium acts as a buffer gas in it. That means Helium doesn’t directly produce laser light, it only helps the atom of the Neon gas to produce lasing in as manner.

  • Helium absorbed some energy, when energy applied to the He – Ne gas mixture, and it achieve an ex

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Question number: 26

» Quantum Mechanics I » Particle in a Finite Well, Linear, Harmonic Oscillator, Reflection

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Appeared in Year: 2011

Essay Question▾

Describe in Detail

Solve the Schrodinger equation for a potential step function given by,

and calculate the reflection and transmission coefficients. Show that for there is a finite probability of finding the particle in a classically forbidden region.

Explanation

  • Consider . The time independent Schrodinger equation in one dimension is given as,

  • And according to question, the potential step function is given as,

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Question number: 27

» Quantum Mechanics II & Atomic Physics » Quantum Mechanics II » The Spin Half Problem and Properties of Pauli Spin Matrices

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Appeared in Year: 2011

Essay Question▾

Describe in Detail

What are Pauli spin matrices?

Show that:

Where, are Pauli spin matrices and and are vector operators which commute with , but do not necessarily commute with each other?

Explanation

Pauli spin matrices or Pauli matrices are a set of matrices, which are complex, Hermitian and unitary matrices. Pauli spin matrices defined as,

The Pauli vector is defi

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