Advertisements
Advertisements
Question
What is Resistivity?
Advertisements
Solution
The resistivity of a conductor is defined as the resistance of a conductor of unit length and unit area of cross-section.
APPEARS IN
RELATED QUESTIONS
What will be the change in the current if the potential difference is kept constant and the resistance of the circuit is made four times?
- It will remain unchanged.
- It will become four times.
- It will become one-fourth.
- It will become half.
Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
Ohm's law gives a relationship between:
(a) current and resistance
(b) resistance and potential difference
(c) potential difference and electric charge
(d) current and potential difference
Fill in the following blank with suitable words:
Resistance is measured in .............. The resistance of a wire increases as the length ..............; as the temperature ..............; and as the cross-sectional area .............. .
A metal sphere is kept on an insulting stands. A negatively charged rod is brought near it, then the sphere is earthed as shown. On removing the earthing, and taking the negatively charged rod away, what will be the nature of charge on the sphere? Give reason for your answer.
Consider the sacle of voltmeter shown in the diagram and answer the following questions :
(a) What is the least count of the voltmeter?
(b) What is the reading shown by the voltmeter ?
(c) If the voltmeter is connected across a resistor of 20 `Omega` how much current is flowing through the resistor?
What is meant by the drift speed of free electrons?
Draw a neat diagram for the verification of Ohm’s law by voltmeter-ammeter method. By another diagram show the relation between p.d. and current.
Choose the correct alternative.
Which of the following is an ohmic conductor?
SI unit of resistance is:
Ohm’s law states the relationship between power and voltage.
State macroscopic form of Ohm’s law.
Define temperature coefficient of resistance.
Which of the following I-V graph represents ohmic conductors?
Which of the following is correct for V-I graph of a good conductor?
The variable resistance is called ____________.
The temperature of a conductor is increased. The graph best showing the variation of its resistance is:
Vinita and Ahmed demonstrated a circuit that operates the two headlights and the two sidelights of a car, in their school exhibition. Based on their demonstrated circuit, answer the following questions.
- State what happens when switch A is connected to:
a) Position 2
b) Position 3 - Find the potential difference across each lamp when lit.
- Calculate the current.
a) in each 12 Ω lamp when lit.
b) In each 4 Ω lamp when lit.
OR - Show, with calculations, which type of lamp, 4.0 Ω or 12 Ω, has the higher power.
