01. Ohm's Law, Resistance, Conductivity and Thermal Dependency of Resistance
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Current Electricity

151900 A cylindrical rod is reformed to half of its original length, keeping volume constant. If its resistance before this change was $R$, then the resistance after reformation of rod will be

1 $\mathrm{R}$
2 $\frac{\mathrm{R}}{4}$
3 $\frac{3 R}{4}$
4 $\frac{R}{2}$
JCECE-2018
Current Electricity

151901 Consider a cylindrical conductor of length $L$ and area of cross-section $A$. The specific conductivity varies as $\sigma(x)=\sigma_{0} \frac{L}{\sqrt{x}}$ where $x$ is the distance along the axis of the cylinder from one of its ends. The resistance of the system along the cylindrical axis is

1 $\frac{2 \sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
2 $\frac{3 \sqrt{\mathrm{L}}}{2 \mathrm{~A} \sigma_{0}}$
3 $\frac{\sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
4 $\frac{2 \sqrt{\mathrm{L}}}{\mathrm{A} \sigma_{0}}$
5 $\frac{4 \sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
Kerala CEE -2018
Current Electricity

151902 The electrical conductivity of a metal is

1 directly proportional to the mean free path
2 directly proportional to the mass of electron
3 inversely proportional to the relaxation time
4 inversely proportional to the mean free path
5 directly proportional to the average speed of free electrons
Kerala CEE -2018
Current Electricity

151903 A wire made of aluminium having resistivity $\rho=2.8 \times 10^{-8} \mathrm{~m}$ with a circular cross-section and has a radius of $2 \times 10^{-3} \mathrm{~m}$. A current of $5 \mathrm{~A}$ flows through the wire. If the voltage difference between the ends is $1 \mathrm{~V}$, What is the length of the wire in meters?

1 50
2 60
3 90
4 120
5 110
Kerala CEE -2018
NEET DIGITAL LIBRARY
Current Electricity

151900 A cylindrical rod is reformed to half of its original length, keeping volume constant. If its resistance before this change was $R$, then the resistance after reformation of rod will be

1 $\mathrm{R}$
2 $\frac{\mathrm{R}}{4}$
3 $\frac{3 R}{4}$
4 $\frac{R}{2}$
JCECE-2018
Current Electricity

151901 Consider a cylindrical conductor of length $L$ and area of cross-section $A$. The specific conductivity varies as $\sigma(x)=\sigma_{0} \frac{L}{\sqrt{x}}$ where $x$ is the distance along the axis of the cylinder from one of its ends. The resistance of the system along the cylindrical axis is

1 $\frac{2 \sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
2 $\frac{3 \sqrt{\mathrm{L}}}{2 \mathrm{~A} \sigma_{0}}$
3 $\frac{\sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
4 $\frac{2 \sqrt{\mathrm{L}}}{\mathrm{A} \sigma_{0}}$
5 $\frac{4 \sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
Kerala CEE -2018
Current Electricity

151902 The electrical conductivity of a metal is

1 directly proportional to the mean free path
2 directly proportional to the mass of electron
3 inversely proportional to the relaxation time
4 inversely proportional to the mean free path
5 directly proportional to the average speed of free electrons
Kerala CEE -2018
Current Electricity

151903 A wire made of aluminium having resistivity $\rho=2.8 \times 10^{-8} \mathrm{~m}$ with a circular cross-section and has a radius of $2 \times 10^{-3} \mathrm{~m}$. A current of $5 \mathrm{~A}$ flows through the wire. If the voltage difference between the ends is $1 \mathrm{~V}$, What is the length of the wire in meters?

1 50
2 60
3 90
4 120
5 110
Kerala CEE -2018
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Current Electricity

151900 A cylindrical rod is reformed to half of its original length, keeping volume constant. If its resistance before this change was $R$, then the resistance after reformation of rod will be

1 $\mathrm{R}$
2 $\frac{\mathrm{R}}{4}$
3 $\frac{3 R}{4}$
4 $\frac{R}{2}$
JCECE-2018
Current Electricity

151901 Consider a cylindrical conductor of length $L$ and area of cross-section $A$. The specific conductivity varies as $\sigma(x)=\sigma_{0} \frac{L}{\sqrt{x}}$ where $x$ is the distance along the axis of the cylinder from one of its ends. The resistance of the system along the cylindrical axis is

1 $\frac{2 \sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
2 $\frac{3 \sqrt{\mathrm{L}}}{2 \mathrm{~A} \sigma_{0}}$
3 $\frac{\sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
4 $\frac{2 \sqrt{\mathrm{L}}}{\mathrm{A} \sigma_{0}}$
5 $\frac{4 \sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
Kerala CEE -2018
Current Electricity

151902 The electrical conductivity of a metal is

1 directly proportional to the mean free path
2 directly proportional to the mass of electron
3 inversely proportional to the relaxation time
4 inversely proportional to the mean free path
5 directly proportional to the average speed of free electrons
Kerala CEE -2018
Current Electricity

151903 A wire made of aluminium having resistivity $\rho=2.8 \times 10^{-8} \mathrm{~m}$ with a circular cross-section and has a radius of $2 \times 10^{-3} \mathrm{~m}$. A current of $5 \mathrm{~A}$ flows through the wire. If the voltage difference between the ends is $1 \mathrm{~V}$, What is the length of the wire in meters?

1 50
2 60
3 90
4 120
5 110
Kerala CEE -2018
For More Updates join with Us
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Current Electricity

151900 A cylindrical rod is reformed to half of its original length, keeping volume constant. If its resistance before this change was $R$, then the resistance after reformation of rod will be

1 $\mathrm{R}$
2 $\frac{\mathrm{R}}{4}$
3 $\frac{3 R}{4}$
4 $\frac{R}{2}$
JCECE-2018
Current Electricity

151901 Consider a cylindrical conductor of length $L$ and area of cross-section $A$. The specific conductivity varies as $\sigma(x)=\sigma_{0} \frac{L}{\sqrt{x}}$ where $x$ is the distance along the axis of the cylinder from one of its ends. The resistance of the system along the cylindrical axis is

1 $\frac{2 \sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
2 $\frac{3 \sqrt{\mathrm{L}}}{2 \mathrm{~A} \sigma_{0}}$
3 $\frac{\sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
4 $\frac{2 \sqrt{\mathrm{L}}}{\mathrm{A} \sigma_{0}}$
5 $\frac{4 \sqrt{\mathrm{L}}}{3 \mathrm{~A} \sigma_{0}}$
Kerala CEE -2018
Current Electricity

151902 The electrical conductivity of a metal is

1 directly proportional to the mean free path
2 directly proportional to the mass of electron
3 inversely proportional to the relaxation time
4 inversely proportional to the mean free path
5 directly proportional to the average speed of free electrons
Kerala CEE -2018
Current Electricity

151903 A wire made of aluminium having resistivity $\rho=2.8 \times 10^{-8} \mathrm{~m}$ with a circular cross-section and has a radius of $2 \times 10^{-3} \mathrm{~m}$. A current of $5 \mathrm{~A}$ flows through the wire. If the voltage difference between the ends is $1 \mathrm{~V}$, What is the length of the wire in meters?

1 50
2 60
3 90
4 120
5 110
Kerala CEE -2018
NEET DIGITAL LIBRARY