Conductivity – Old Year Questions

1. Which element is the best conductor of electricity?

(a) Silver
(b) Copper
(c) Aluminium
(d) Iron

[Chhattisgarh P.C.S. (Pre) 2011, M.P.P.C.S. (Pre) 1990]


2. Which one of the following is the best conductor of electricity?

(a) Mica
(b) Copper
(c) Gold
(d) Silver

[U.P.P.C.S. (Mains) 2015]


3. Assertion (A): Copper rods are generally preferred to iron rods for making lightning conductors.
Reason (R): Copper is a better conductor of electricity than iron and is not easily oxidized under atmospheric conditions.

Code :

(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[U.P.R.O./A.R.O. (Mains) 2013]


4. The characteristic of a superconductor is –

(a) High permeability
(b) Low permeability
(c) Zero permeability
(d) Infinite permeability

[39th B.P.S.C. (Pre) 1994]


5. At which temperature superconductivity can be of tremendous economic interest saving billions of rupees?

(a) At very low temperature
(b) At a temperature when semiconductor becomes a superconductor
(c) at room temperature
(d) At a very high temperature

[U.P.P.C.S. (Pre) 2000]


6. The highest temperature attained by a superconductor is :

(a) 24 K
(b) 133 K
(c) 150K
(d) 300K

[U.P. Lower Sub. (Pre) 2013]


7. The newly discovered high-temperature superconductors are –

(a) Metal alloys
(b) Pure rare earth metals
(c) Ceramic oxides
(d) Inorganic polymers

[Uttarakhand P.C.S. (Pre) 2006, U.P.P.C.S. (Pre) 2000]


8. The conductivity of a semiconductor at zero Kelvin is–

(a) 105 ohm
(b) 10-1 ohm
(c) 10-5 ohm
(d) zero

[R.A.S./R.T.S. (Pre) 1999-2000]


9. The resistance of a semiconductor on heating :

(a) Remains constant
(b) Decreases
(c) Increases
(d) None of the above

[U.P.P.C.S. (Mains) 2015]


10. On heating, the resistance of a semiconductor :

(a) increases
(b) decreases
(c) remains same
(d) first increases and then decreases
(e) None of the above / More than one of the above

[66th B.P.S.C. (Pre) 2020]


11. Electric conduction in a semiconductor takes place due to

(a) Electrons only
(b) Holes only
(c) Both electrons and holes
(d) Neither electrons nor holes

[Uttarakhand P.C.S. (Pre) 2016]


12. At absolute zero temperature, the electric resistance in a semiconductor is-

(a) Infinite
(b) Meager
(c) High
(d) Zero

[R.A.S./R.T.S. (Pre) 1992]


13. Which one of the following metals is used as a semiconductor in transistors?

(a) Copper
(b) Germanium
(c) Graphite
(d) Silver

[44th B.P.S.C. (Pre) 2000]


14. The most commonly used material for making transistors is –

(a) Aluminium
(b) Silicon
(c) Copper
(d) Silver

[U.P.P.C.S. (Pre) 2015]


15. Which one of the following is an important component of a transistor?

(a) Arsenic
(b) Germanium
(c) Osmium
(d) Radium

[U.P. R.O./A.R.O. (Pre) 2016]


16. Which of the following are semiconductors?

1. Silicon
2. Quartz

3. Ceramics
4. Germanium

Choose the correct answer from the following alternatives:

(a) 1 and 2
(b) 1 and 3
(c) 1 and 4
(d) 3 and 4

[U.P.P.C.S. (Mains) 2005]


17. Which of the following is a semiconductor?

(a) Plastic
(b) Aluminium
(c) Wood
(d) Germanium

[U.P.P.C.S. (Pre) (Re. Exam) 2015]


18. Which of the following elements is a semiconductor?

(a) Aluminium
(b) Silicon
(c) Silver
(d) Lead

[U.P. P.C.S. (Pre) 2018]


19. The Government of India has totally banned the export of burnt coal (Jhama) because it contains recoverable amounts of metal/element that is used in transistors. Which one of the following is that element?

(a) Phosphorus
(b) Germanium
(c) Silicon
(d) Tungsten

[I.A.S. (Pre) 1993]