Super Conductors

Question 1

The phenomena of super conductors was first discovered by ___________
a) Kammerlingh Onnes
b) Neils bohr
c) Richard Smalley
d) Otto lehman

Answer 1

Kammerlingh Onnes

Richard Smalley discovered the fullerene by laser ablation method.

Question 2

Super conductors are discovered in the year _______
a) 1900
b) 1991
c) 1911
d) 1905

Answer 2

1911

Super conductors are discovered in the year 1911 by Kammerlingh Onnes. He is a Dutch physicist. When he was measuring the resistivity of the mercury below 4.2K he found the super conductors.

Question 3

The earliest superconductors to be studied elaborately is ________
a) Niobium alloy
b) Copper alloys
c) Steel alloys
d) Iron alloy

Answer 3

Niobium alloy

Question 4

The shifting of electrons in super conductors is prevented by _________
a) Quantum effect
b) Threshold energy level
c) Energy barrier
d) Orbitals

Answer 4

Quantum effect

Question 5

The normal metal passes into super conducting state at ___________
a) High temperature
b) Low temperature
c) Critical temperature
d) No temperature

Answer 5

Critical temperature

Question 6

Based on magnetic response super conductors are of __________ types.
a) 1
b) 2
c) 3
d) 4

Answer 6

b) 2

Type 1 - ideal (Soft) super conductors
Type 2 - hard super conductors.

Question 7

Ideal super conductors completely become __________ at super conducting state.
a) Diamagnetic
b) Ferro magnetic
c) Ferri magnetic
d) Para magnetic

Answer 7

Diamagnetic

Question 8

The ideal super conductors exhibit __________
a) Meissner effect
b) Mesmeric effect
c) Mesomeric effect
d) Monomeric effect

Answer 8

Meissner effect

The expulsion of magnetic flux from the interior of a piece of super conducting material as the material undergoes transition to super conducting phase.

Question 9

The hard super conductors are those in which the ideal behaviour is seen up to a ________ critical magnetic field.
a) Higher
b) Lower
c) Moderate
d) Zero

Answer 9

Lower

The hard super conductors are those in which the ideal behaviour is seen up to a lower critical magnetic field beyond which the magnetization gradually changes and attains zero.

Question 10

In superconductors, the Fermi energy level is

a. Below the ground state
b. Midway between the ground state and first excited state
c. Above first excited state
d. At first excited state

Answer 10

Midway between the ground state and first excited state

Question 11

The superconducting state is perfectly _____ in nature.

Diamagnetic
Paramagnetic
Ferromagnetic
Ferromagnetic

Answer 11

Diamagnetic

magnetic susceptibility = -1

Question 12

Which of the following are the properties of superconductors?

They are diamagnetic in nature
They have zero resistivity
They have infinite conductivity
All of the above

Answer 12

All of the above

Question 13

The minimum amount of current passed through the body of superconductor in order to destroy the superconductivity is called

Induced current
Critical current
Eddy current
Hall current

Answer 13

Critical current

Question 14

The energy required to break a cooper pair is ___ of the energy gap of superconductor.

One half
Equal to
Twice
Thrice

Answer 14

Equal to

Question 15

The binding energy for a cooper pair is

10^-2 eV
10^-4 eV
10^-6 eV
10^-8 eV

Answer 15

10^-4 eV

Question 16

The magnetic lines of force cannot penetrate the body of a superconductor, a phenomenon is known as

Isotopic effect
BCS theory
Meissner effect
London theory

Answer 16

Meissner effect

Question 17

Which of the following conductor has highest critical temperature?

Aluminium
Zinc
Molybdenium
Tin

Answer 17

Tin

Question 18

The magnetization ‘M’ of a superconductor in a filed H is

(a) extremely small
(b) -H
(c) -1
(d) Zero

Answer 18

(b) -H

in superconductors, B=0
μ(H+M)=0

Question 19

If a small amount of Cu is added to a Ni conductor then the

(a) the resistivity of Ni will increase at all temperatures because Cu is a better conductor than Ni
(b) residual resistivity of Ni at low temperatures will increase as Cu atoms act as defect centers
(c) the resistivity of Ni will increase at all temperatures as Cu destroys the periodicity of Ni and acts as defects
(d) the resistivity of Ni remains unaltered as Cu atoms give the same number of free electrons as Ni atoms

Answer 19

the resistivity of Ni will increase at all temperatures as Cu destroys the periodicity of Ni and acts as defects

Question 20

Which one of the following is the best definition of a superconductor?

(a) it is a material showing perfect conductivity and the Meissner effect below a critical temperature
(b) It is a conductor having zero resistance
(c) It is a perfect conductor with the highest diamagnetic susceptibility
(d) It is a perfect conductor but becomes resistive when the current density through it exceeds a critical value

Answer 20

it is a material showing perfect conductivity and the Meissner effect below a critical temperature

Question 21

The correct sequence of the following materials in the increasing order of magnetic susceptibility is

(a) Diamagnetic – Ferromagnetic – Paramagnetic – Superconductor
(b) Ferromagnetic – Paramagnetic – Diamagnetic – Superconductor
(c) Paramagnetic – Diamagnetic – Superconductor – Ferromagnetic
(d) Superconductor – Diamagnetic – Paramagnetic – Ferromagnetic

Answer 21

Superconductor – Diamagnetic – Paramganetic – Ferromagnetic

Question 22

Superconductors are becoming popular of their use in

(a) generating a very strong magnetic field
(b) manufacture of bubble memories
(c) generating electrostatic field
(d) generating regions free from the magnetic field

Answer 22

generating a very strong magnetic field

Question 23

The dc resistivity and permeability exhibited by a type-I superconductor are respectively

(a) Zero and Zero
(b) Zero and unity
(c) Unity and Zero
(d) Unity and Unity

Answer 23

Zero and Zero