# GATE Physics: Questions 81 - 84 of 168

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## Question number: 81

» Electromagnetic Theory » Energy and Momentum of Electromagnetic Waves

Appeared in Year: 2014

### Write in Short

The intensity of a laser in free space is . The corresponding amplitude of the electric field of the laser is .

## Question number: 82

» Mathematical Physics » Vector Calculus

Appeared in Year: 2014

### Write in Short

If the vector potential

satisfies the Coulomb gauge, the value of the constant is ________.

## Question number: 83

» Quantum Mechanics » Angular Momentum and Spin

Appeared in Year: 2015

### Write in Short

Let the Hamiltonian for two spin particles of equal masses , momenta and and position and be

where and denote the corresponding Pauli matrices, and . If the ground state has net spin zero, then the energy (in ) is ________.

## Question number: 84

» Solid State Physics » Elements of Superconductivity » Type-I and Type-II Superconductors

Appeared in Year: 2015

### Question

Which one of the following represents the electron occupancy for a superconductor in its normal and superconducting states?

### Choices

Choice (4) | Response | |
---|---|---|

a. | ||

b. | ||

c. | ||

d. |