  # Conducting materials MCQ with answers - Numericals - Part 3

This sets of mcq includes conducting materials, general properties of conductor, superconductivity and numericals in part 3...

## SET 1 of Conducting materials MCQ

1. A nichrome wire used as heater coil has the resistance of 1 ohm/m. For a heater of 1000 W at 200 V, the length of wire required will be
A. 10 m
B. 20 m
C. 40 m
D. 80 m

Marks 2

2. The electrical resistance of metals ---(i)--- & the electrical resistance of semiconductor and electrolyte -----(ii)-----
A. i) decreases with increases with temperature & ii) decreases with decrease in temperature
B. i) & ii) both increases with temperature
C. i)increases with increase in temperature & ii) decreases with increase in temperature
D. i)increases with decrease in temperature & ii) decreases with decrease in temperature

Marks 2

3. The shunt winding of a motor has a resistance of 85 ohm at 220C. When the motor runs at full load, its resistance increases to 100 ohms. The resistance temperature coefficient of winding per 00C is 0.004. The rise in temperature of the winding will be nearly----
A. 20oC
B. 50oC
C. 100oC
D. 70oC

Marks 2

4. The temperature coefficient of resistance of a wire is 0.00125/ ºC. At 300K, its resistance is 1 Ω. The resistance of the wire will be 2 Ω at----
A. 1154K
B. 1100K
C. 1127K
D. 1400K

Marks 2

5. A 100 W, 200 V filament lamp has operating temperature of 2000oC. The filament material has resistance temperature coefficient of 0.005 at 0oC per oC. The current taken by the lamp
at the instant of switching with 200 V supply with filament temperature of 20oC will be----
A. 5 A
B. 3 A
C. 1 A
D. 10 A

Marks 2

6. Match the following :
Column 1                 Column 2
a) Copper                  i. Resistors
b) Salt Solution         ii. Electrolytic Conductor
c) Germanium          iii. Good Conductor
d) Ferronickel alloys iv. Semi-Conductors
A. a-(i), b-(ii), c-(iii), d(iv)
B. a-(ii), b-(iii), c-(iv), d-(i)
C. a-(iii),b-(i), c-(ii), d-(iv)
D. a-(iii), b-(ii) c-(iv), d-(i)

Marks 2

7. The resistance between the opposite faces of 1 m cube is found to be 1 Ω. If its length is increased to 2 m, with its volume remaining the same, then its resistance between the opposite faces along its length is----
A. 1 Ω
B. 2 Ω
C. 4 Ω
D. 8 Ω

Marks 2

8. The following list gives the four metals gold (Au), silver (Ag), aluminium (Al) and copper (Cu) in increasing order of resistivity
A. Ag, Cu, Au, Al
B. Au, Ag, Cu, Al
C. Ag, Au, Cu, Al
D. Cu, Ag, Au, Al

Marks 2

9. Conductivity of Insulator, Semiconductors & conductors are of the order of
A. , &
B. , &
C. , &
D. , &

Marks 2

10. Nichrome is a composition of
A. 75-78% Ni, 20-30% Cr, 1.5% Mn, Remainder Fe
B. 20-30% Ni, 75-78% Cr, 3& Fe & Mn
C. 60-70 Ni, 30-40 Cr
D. None

Marks 2

## SET 2 of Conducting materials MCQ

11. Copper –constantan & Iron- constantan thermocouple are used up to --------& -------- 0C respectively
A. 250 to 400 & 200 to 850
B. 200 to 1100 & 0 to 1400
C. 0 to 2600 & 0 to 1400
D. 200 to 850 and 200 to 1100

Marks 2

12. Melting point of soldering material should be
A. Higher than that of material to be jointed
B. Lower than that of material to be jointed
C. Lower & higher than that of material to be jointed
D. None

Marks 2

13. Melting points of soft & hard solders are ---- 0C & ---- 0C
A. Lower than 400 & higher than 400
B. Higher than 400 & lower than 400
C. Lower than 600 & higher than 800
D. Higher than 300 & lower than 500

Marks 2

14. Chromel-Alumel & Platinum- Rhodium thermocouple are used up to ------ 0C & -------- 0C respectively.
A. 250 to 400 & 200 to 850
B. 200 to 1100 & 0 to 1400
C. 0 to 2600 & 0 to 1400
D. 200 to 850 & 200 to 1100

Marks 2

15. Energy band gap size for semiconductors is in the range ________ eV.
A. 1-2
B. 2-3
C. 3-4
D. > 4

Marks 2

16. Gunmetal is an alloy of
A. 70% Cu + 20% Zn + 10% Sn
B. 86% Cu + 9% Zn + 5% Sn
C. 90% Cu + 1% Zn + 5% Sn
D. 99% Cu + 0.5% Zn + 0.5% Sn

Marks 2

17. German silver is an alloy of
A. copper, manganese, nickel
B. silver, tin & tungsten
C. copper, zinc, nickel
D. copper, silver, aluminum

Marks 2

18. The resistivity of wire material having length of 1m and diameter of 0.08mm and resistance of 95.5Ω is----
A. 4.79*10-5 Ωm
B. 4.79*10-7 Ωm
C. 4.79*10-6 Ωm
D. 4.79*10-8 Ωm

Marks 2

19. Consider the statements Superconductivity in a material can be destroyed by
1) Increasing the temperature above certain limit
2) Applying magnetic field above certain limit
3) Passing large current above the rated through the material
4) Decreasing the temperature to point below critical temperature
A. 2, 3 & 4 are correct
B. 1, 3 & 4 are correct
C. 1, 2 & 3 are correct
D. 1, 2 & 4 are correct

Marks 2

20. Consider the following properties pertaining to an alloy used as precision resistor
1) Uniform resistance
2) Stable resistance
3) Zero or low temperature co-efficient of resistivity
Which of these properties are desirable?
A. 1,2 & 3
B. 1 & 2
C. 1 & 3
D. 2 & 3

Marks 2