# GATE (Graduate Aptitude Test in Engineering) Physics: Questions 274 - 278 of 659

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### Passage

A plane electromagnetic wave has the magnetic field given by,

where, is the wave number and are the Cartesian unit vector in directions, respectively.

## Question 274 (2 of 2 Based on Passage)

Appeared in Year: 2011

### Question

MCQ▾

The electric field corresponding to the above wave is given by –

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question 275

Appeared in Year: 2010

### Question

MCQ▾

The value of the integral , where the contour is the unit circle | |= 1 is –

### Choices

Choice (4)Response

a.

b.

c.

0

d.

## Question 276

Appeared in Year: 2010

### Question

MCQ▾

The Bloch theorem states that within a crystal, the wavefunction, of an electron has the from –

### Choices

Choice (4)Response

a.

where is an arbitrary function and is a reciprocal lattice vector

b.

where , is a lattice and is a reciprocal lattice vector

c.

where , is a lattice vector and is an arbitrary vector

d.

, where is an arbitrary function and is an arbitrary vector

## Question 277

Covariant and Contravariant Tensor

Appeared in Year: 2010

### Question

MCQ▾

Consider an anti – symmetric tensor with the indices and running from to . The number of independent components of the tensor is –

### Choices

Choice (4)Response

a.

9

b.

3

c.

6

d.

10

## Question 278

Appeared in Year: 2010

### Question

MCQ▾

Two states of an atom have definite parities. An electric dipole transition between these states is

### Choices

Choice (4)Response

a.

Allowed if both the states have even parity

b.

Allowed if both the states have odd parity

c.

Not allowed unless a static electric field is applied

d.

Allowed if the two states have opposite parities

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