Conductivity and Resistivity

The resistances in the two arms of the meter bridge are $5\Omega andR\Omega$, respectively. When the resistance R is shunted with an equal resistance, the new balance point is at 1.6, the resistance R is

1. $10\Omega$

2. $20\Omega$

3. $25\Omega$

4. $15\Omega$

How can three resistors of resistances $2\Omega ,3\Omega$ and $6\Omega$ be connected to give a total resistance of $1\Omega$?

What is Cell Constant?

A silver wire has a resistance of 2.1 Ω at 27.5 °C, and a resistance of 2.7 Ω at 100 °C. Determine the temperature coefficient of resistivity of silver.

1. The electron will experience a force at ${45}^{\circ }$ to the axis and hence execute a helical path.
2. The electron path will be circular about the axis.
3. The electron will continue to move with uniform velocity along the axis of the solenoid
4. The electron will be accelerated along the axis.

1. $4\Omega ,8\Omega$
2. $8\Omega ,4\Omega$
3. $6\Omega ,9\Omega$
4. $9\Omega ,6\Omega$

Two capacitors with capacitance values ${\mathrm{C}}_1=2000\pm 10\mathrm{pF}$ and ${\mathrm{C}}_2=3000\pm 15\mathrm{pF}$ are connected in series. The voltage applied across this combination is 𝑉 = 5.00 ± 0.02 V. The percentage error in the calculation of the energy stored in this combination of capacitors is _______.

Two identical metal wires of thermal conductivities $K_1$ and $K_2$ respectively are connected in series. The effective thermal conductivity of the combination is:

1. $\frac{2K_1{K}_2}{K_1+K_2}$

2. $\frac{K_1+K_2}{K_1{K}_2}$

3. $\frac{K_1+K_2}{2K_1{K}_2}$

4. $\frac{K_1{K}_2}{K_1+K_2}$

The specific resistance of manganin is

$50\times {10}^{-8}\Omega m$.

The resistance of a manganin cube having length

50 cm is

1. ${10}^{-6}\Omega$
2. $2.5\times {10}^{-5}\Omega$
3. ${10}^{-8}\Omega$
4. $5\times {10}^{-4}\Omega$

1. $0.06{\left({}^{\circ }C\right)}^{-1}$
2. $0.08{\left({}^{\circ }C\right)}^{-1}$
3. $0.01{\left({}^{\circ }C\right)}^{-1}$
4. $0.04{\left({}^{\circ }C\right)}^{-1}$

1. $\frac{\sqrt{5}R}{2},{\tan }^{-1}\left(2\right)$
2. $\sqrt{5}R,{\tan }^{-1}\left(\frac{1}{2}\right)$
3. $\frac{\sqrt{5}R}{2},{\tan }^{-1}\left(\frac{1}{2}\right)$
4. $\sqrt{5}{X}_C,{\tan }^{-1}\left(2\right)$

1. $\frac{{\rho }_1+{\rho }_2}{2}$
2. $\sqrt{{\rho }_1{\rho }_2}$
3. ${\rho }_1+{\rho }_2$
4. None of the above

Unit of electric susceptibility?

1. ${10}^{-8}\Omega \text{m}$
2. ${10}^{-7}\Omega \text{m}$
3. ${10}^{-5}\Omega \text{m}$
4. ${10}^{-6}\Omega \text{m}$

The resistivity of the metallic conductor is given by the relation

A cylindrical conductor of length $‘l’$ and uniform area of cross-section $‘A’$ has resistance $‘R’$. The area of cross-section of another conductor of the same material and same resistance but of length $‘2l’$ is

1. $\frac{A}{2}$

2. $\frac{3A}{2}$

3. $2A$

4. $3A$

1. $1\%$
2. $0.2\%$
3. $2\%$
4. $0.1\%$

which of the following has low resistivity

1. copper

2. silver

3. manganin

4. constantan

How does dielectric affect energy stored?

Does the energy stored in a capacitor increase when the dielectric is removed?

1. $6.4\text{M}\Omega \pm 5\%$
2. $64\text{M}\Omega \pm 10\%$
3. $530\text{k}\Omega \pm 5\%$
4. $5.3\text{k}\Omega \pm 5\%$

Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. What is the ratio of heat produced in series and parallel combinations?

State the conditions under which Ohms law is not obeyed in a conductor.

What cause of resistance in a conductor?

What do you mean by the dynamic resistance of a conductor?