## Labels

### Current Electricity : MCQ ON RESISTANCE AND RESISTIVITY

Resistance is a measure of the opposition to current flowing in an electric circuit. It is measured in ohm, symbolised by Greek word omega (Ω). But the quantity more basic than resistance is resistivity. It will be independent of the geometry of the conductor. It depends only on the nature of material of the conductor and temperature of the conductor.

It has been found that the resistance R of a conductor depends upon

1. Directly proportional to the Length of the conductor

R ∝ l(length )

2. Inversely proportional to Area of cross section of conductor

R ∝ 1 / A (Area)

R = ρ L/ A

Where ρ is known as specific resistance or electrical resistivity of the

material of conductor

Q1 Resistance of a conductor depends directly upon

• Pressure
• area
• length
• relaxation time

• length

Q2 With increase in area of cross section ,the resistance of the conductor

• Increases
• decrease
• remain same
• None of these

• decrease

Q3 Resistivity of a conductor varies inversely with

• Nature of material
• area
• length
• none of above

• area

Q4 Resistivity of semiconductors

• Decrease with temperature
• increase with temperature
• no change
• None of the above

• Decrease with temperature

Q5 Resistivity of  conductors

• Decrease with temperature
• increase with temperature
• no change
• None of the above

• increase with temperature

Q6 Electrical resistivity is also known as ..............resistance

• Small resistance
• Large resistance
• shunt
• Specific

• Specific

Q7 Resistance has SI unit as

• Ohm meter
• ohm
• mho
• none of these

• ohm

Q8 Resistivity  has SI unit as

• Ohm meter
• ohm
• mho
• none of these

• Ohm meter

Q9 Resistivity is independent of temperature (True/False)

• True
• false

• False

Q10 Resistance depends upon length of conductor (T\F)

• True
• false

• True