Advertisements
Advertisements
प्रश्न
What length of copper wire of resistivity 1.7 × 10-8 Ω m and radius 1 mm is required so that its resistance is 2Ω?
Advertisements
उत्तर
Resistance (R) = 2 ohm
Resistivity (ρ) = 1.7 × 10-8 ohm metre
Radius (r) = 1 mm = 10-3 m
Length (l) = ?
`R=ρ l/A`
`ρ=l/(pir^2)`
Substituting the values in the formula above we get,
`2 = 1.7xx10^-8l/(pi(10^-3)^2)`
`2 = 1.7xx10^-8l/(3.14xx(10^-3)^2)`
`2=(1.7xx10^-2xxl)/3.14`
`2 =(1.7xxl)/314`
⇒ l = `(314xx2)/1.7`
⇒ l = 369.4 m
Hence, the length of the copper wire = 369.4 m.
संबंधित प्रश्न
If the potential difference across the ends of a conductor is 220 V and the resistance of the conductor is 44 Ω (ohm), then the current flowing through is _________.
- 0.2 A
- 0.5 A
- 2 A
- 5 A
Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it?
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Calculate the value of the resistance of the resistor.
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.
State Ohm’s law? How can it be verified experimentally? Does it hold good under all conditions? Comment.
A heater of 220 V heats a volume of water m 5 mint time. A heater of 110 V heat in ten second. The resistance of the conductor is
You are provided with a resistor, a key, an ammeter, a voltmeter, four cells of 1.5 V each and few connecting wires. Using circuit components, draw a labelled circuit diagram to show the setup to study Ohm's law.
State the relationship between potential difference (V) across the resistor and the current (I) flowing through it. Also draw V-I graph, taking V on the X-axis.
How is electric current related to the potential difference across the terminals of a conductor?
Draw a labelled circuit diagram to verify this relationship.
