Questions 181–190 of 650. Imported answers require independent review unless marked reviewed.

Topic practice 650 questionsPage 19 of 65

Question 51

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and

(

) are contravariant and covariant vectors, respectively. By convention, any repeated indices are summed over. Which of the following expression is/are tensors?
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Question 52

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The temperature T dependence of magnetic susceptibility

(Column I) of certain magnetic materials (Column II) are given below.
Diagram for Physics question 52

Which of the following option is/are correct?
Column I: (1)

decreases from a maximum as

increases; (2)

decreases with increasing

; (3)

is constant; (4)

decreases from a large value as

increases.
Column II: (P) Diamagnetic; (Q) Paramagnetic; (R) Ferromagnetic; (S) Antiferromagnetic.
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Question 53

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The curves P and Q schematically show the variation of X-ray intensity with wavelength at two different accelerating voltages for a given target material. In the figure

,

,

, and

. Take Planck’s constant as

Js, speed of light as

and elementary charge as

C.
Diagram for Physics question 53

Which of the following statement is/are true?
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Question 54

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Apart from the acoustic modes, 9 optical modes are identified from the measurements of phonon dispersions of a solid with chemical formula

, where

and

denote the atomic species, and

and

are integers. Which of the following combination of n and m is/are possible?
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Question 55

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An oscillating electric dipole of moment

is placed at origin as shown in figure.
Diagram for Physics question 55

Consider a point

at a very large distance from the dipole. Here

and

are spherical polar coordinates. Which of the following statement/s are true for intensity of radiation?
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Question 56

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The Fourier transform and its inverse transform are respectively defined as

and

. Consider two functions

and

. Another function

is defined as

Which of the following relation/s are true? Note: Tilde (

) denotes the Fourier transform.
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Question 57

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A material behaves as a superconductor below a critical temperature

and as a normal conductor above

. A magnetic field

is applied when

. The material is then cooled below

in the presence of

. Which of the following figure represent the correct configuration of magnetic field lines?
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Question 58

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A typical biasing of a silicon transistor is shown in figure.
Diagram for Physics question 58

The value of common-emitter current gain

for the transistor is 100. Ignore reverse saturation current. The output voltage

(in V) is ______ (in integer).

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Question 59

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The canonical partition function of an ideal gas is

where

and

denote temperature, volume, number of particles, and thermal de Broglie wavelength, respectively. Let

be the Boltzmann constant and

be the chemical potential. Take

. If the number density

is

at a temperature

, then

is ______

(rounded off to one decimal place).

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Question 60

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Lagrangian of a particle of mass

is

, where

is a positive constant. If the particle oscillates with total energy

, then the time period of oscillations is

The value of

is _____ (in integer).

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