21. Materials that easily allow the passage of electric current are known as ______
A. Insulators
B. Conductors
C. Dielectrics
D. Semi-conductors
22. A wire of length 2m and another wire of length 5m are made up of the same material and have the same area of cross-section, which wire has higher resistance?
A. Both have equal resistance
B. The 2m wire has higher resistance
C. The 5m wire has higher resistance
D. The value of resistance cannot be determined from the given data
23. A wire having an area of cross-section = 10sqm and another wire having an area of cross-section = 15sqm, have the same length and are made up of the same material. Which wire has more resistance?
A. Both have equal resistance
B. The 10sqm wire has higher resistance
C. The 15sqm wire has higher resistance
D. The value of resistance cannot be determined from the given data
24. Which of the following statements are true with regard to resistance?
A. Resistance is directly proportional to the length of the wire
B. Resistance is directly proportional to an area of a cross-section of the wire
C. Resistance is inversely proportional to the length of the wire
D. Resistance is inversely proportional to the resistivity of the wire
25. A wire has the same resistance as the one given in the figure. Calculate its resistivity if the length of the wire is 10m and its area of the cross-section is 2m.
A. 16 ohm − meter
B. 8 ohm − meter
C. 16 kiloohm − meter
D. 8 kiloohm − meter
26. Which, among the following is a unit for resistivity?
A. ohm/meter
B. ohm/meter2
C. ohm − meter
D. ohm − meter2
27. What is the resistivity of Copper?
A. 1.59 × 10 − 8ohm − m
B. 2.7 × 10 − 8ohm − m
C. 7.3 × 10 − 8ohm − m
D. 5.35 × 10 − 8ohm − m
28. Calculate the ratio of the resistivity of 2 wires having the same length and same resistance with an area of cross-section of 2m2 and 5m2 respectively.
A. 5:7
B. 2:7
C. 2:5
D. 7:5
29. Which of the following statements are true with regard to resistivity?
A. Resistance depends on the temperature
B. Resistance does not depend on the temperature
C. Resistivity depends on the length
D. Resistivity depends on the area of cross-section
30. The reciprocal of resistivity is________
A. Conductance
B. Resistance
C. Conductivity
D. Impedance