1. Resistivity of a material depend on
(A) nature of material.
(B) area of the conductor section.
(C) length of the conductor.
(D) all of the above.
Answer ⇓
2. Negatively charged particle present in an atom is
(A) Molecule.
(B) Proton.
(C) Neutron.
(D) Electron.
Answer ⇓
3. Which of the following metal have lowest temperature coefficient of resistance?
(A) gold.
(B) copper.
(C) aluminium.
(D) kanthal.
Answer ⇓
4. The material preferred for transmitting electrical energy over long distance is
(A) copper.
(B) aluminium.
(C) steel reinforced copper.
(D) steel reinforced aluminium.
Answer ⇓
5. The conductivity of a conductor can be increased by
(A) decreasing its temperature.
(B) increasing its temperature.
(C) decreasing its vibration.
(D) increasing its vibration.
Answer ⇓
6. Superconductivity is observed for
(A) infrared frequencies.
(B) d.c. and low frequency.
(C) a.c. and high frequency.
(D) frequencies having no effect.
Answer ⇓
7. Which of the following resistive materials has the lowest temperature co-efficient of resistance ?
(A) Nichrome.
(B) Constantan.
(C) Kanthal.
(D) Molybdenum.
Answer ⇓
8. The coils of D.C. motor starter are wound with wire of
(A) copper.
(B) manganin.
(C) kanthal.
(D) nichrome.
Answer ⇓
9. Which of the following material has the highest dielectric strength?
(A) Oiled Paper.
(B) Mica.
(C) Glass.
(D) Air.
Answer ⇓
10. With the decrease in magnetic intensity the relative permeability of a magnetic material
(A) decreases.
(B) increases.
(C) become zero.
(D) remain the same.
Answer ⇓
11. Which of the following dielectric material is used in the transformers?
(A) Paraffin.
(B) Porcelain.
(C) Air.
(D) Oiled Paper.
Answer ⇓
12. Which of the following is a paramagnetic material?
(A) Bismuth.
(B) Copper.
(C) Carbon.
(D) Oxygen.
Answer ⇓
13. Which of the following is a diamagnetic material?
(A) Aluminium.
(B) Silver.
(C) Air.
(D) Cobalt.
Answer ⇓
14. Which of the following magnetic material is used to made the permanent magnets?
(A) Iron.
(B) Soft steel.
(C) Hardened steel.
(D) Nickel.
Answer ⇓
15. Soldering wires are generally made of
(A) steel-tin alloy.
(B) aluminium.
(C) copper.
(D) lead-tin alloy.
Answer ⇓
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