EASY
Earn 100

What is the formula of resistance?

Important Questions on Electricity

MEDIUM
Resistance of a metal wire of length 1 m is 26 Ω at 20°C. If the diameter of the wire is 0.3 mm, What will be the resistivity of the metal at that temperature?
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Establish relation between potential difference V and electric current I by plotting graph.

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Name the factors affecting the resistance of a conductor.
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A wire of resistance 1000 Ω and length l is increased to twice its original length. Calculate its new resistance.
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A V-I graph for a nichrome wire is given below. What do you infer from this graph? Draw a labelled circuit diagram to obtain such a graph.

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MEDIUM
What is resistivity? Write the formula of resistivity. Write the SI unit of resistivity.
EASY
Define the resistivity of a substance.
EASY

On what factors does the resistance of a conductor depends?

EASY
 List the factors on which the resistance of a conductor depends.
EASY
Why are alloys commonly used in electrical heating devices? Give reason.
EASY
An electric bulb of resistance 80 Ω draws a current of 0.75 A. Find the line voltage. 
EASY
How does an increase in the temperature affect the specific resistance of a metal?
MEDIUM

Write the S.I. unit of resistivity. An electric motor takes 5 A from a 220 V source. Determine the power of the motor and energy consumed in 2 hours.

EASY
Electrical resistivity of a given metallic wire depends upon
EASY
Name a substance whose resistance decreases with the increase in temperature.
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Following figures shows graph of I-V. Which graph is correct according to Ohm's law?

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EASY
In one circuit, resistance of wire is 10 Ω. If it is connected with 2.5 V battery, how much electric current will flow through it?
EASY

Write Ohm's law.

MEDIUM

The values of current (I) flowing through a given resistor of resistance (R), for the corresponding values of potential difference (V) across the resistor, are as given below:

V (volts) 0.5 1.0 1.5 2.0 2.5 3.0 4.0 5.0
A(amperes) 0.1 0.2 0.3 0.4 0.5 0.6 0.8 1.0

Plot a graph between current (I) and potential difference (V) and determine the resistance (R) of the resistor.

MEDIUM
How does an increase in the temperature affect the specific resistance of a Semiconductor?