Resistance

Q. Calculate the resistance of copper wire ​having a length of $1\text{km}$ and diameter $0.5\text{mm}$.​
(Resistivity of copper $=1.7\times {10}^{-8}\Omega \text{m}$)

1. $50\Omega$
2. $60\Omega$
3. $85\Omega$
4. $75\Omega$

Q.

A copper wire has a diameter of $0.5mm$ and resistivity of $1.6\times {10}^{-8}\Omega m$ What will be the length of this wire to make its resistance $10\Omega ?$ How much does the resistance change if the diameter is doubled?

Q.

A $6\Omega$ resistance wire is doubled by folding. What is the new resistance?

Q.

Calculate the resistance of 1 km long copper wire of radius 1 mm. (Take specific resistance of copper $=1.72\times {10}^{-8}\Omega m$)

1. $6.5\text{ohm}$

2. $7.5\text{ohm}$

3. $5.5\text{ohm}$

4. $4.5\text{ohm}$

Q.

A steady current flows in a metallic conductor of the non-uniform cross-section. The quantity/quantities constant along the length of the conductor is/are

1. current, electric field and drift speed

2. drift speed only

3. current and drift speed

4. current only

Q.

State and define the S.I. unit of resistance.

Q.

Name and define the SI unit of resistance

Q.

What is the dimensional formula of ‘rate of flow’?

Q.

Judge the equivalent resistance when the following are connected in parallel, 1 Ω and 10³Ω and 10⁶Ω.

Q.

What Is Earth Resistance?

Q.

"The resistance of a wire is 1 ohm. Explain the meaning of this statement.

Q. By doubling the voltage across a resistor, one can obtain double the current of initial value. What can be said about resistance of the resistor?

1. Resistance is doubled
2. Resistance is halved
3. Resistance is unchanged
4. Resistance cannot be determined

Q.

Which device is used in a circuit to vary the resistance continuously?

1. Ammete

2. Rheostat

3. Galvanometer

4. Tapping key

Q.

Does copper have a high resistance?

Q.

According to ohms law:

1. Current will increase by increasing voltage in circuit

2. Resistance will increase by increasing voltage in circuit

3. Resistance will increase by increasing current in circuit

4. Resistance and current both will increase by increasing voltage

Q.

How is the resistance of a wire affected if its length is doubled?

1. becomes one-fourth

2. becomes four times

3. becomes half

4. becomes twice

Q.

The resistance of a $1m$ long nichrome wire is $6\Omega$. If we reduce the length of wire to $70cm,$ what will be its new resistance?

1. $4.2\Omega$

2. $2.4\Omega$

3. $6.2\Omega$

4. $3.2\Omega$

Q.

On increasing the resistance in a circuit, the current in it ___.

1. decreases

2. increases

3. will remain same

4. first increases and then decreases

Q.

Match List I with List II

Column 1	Column 2
(a) Rectifier	(i) Used either for stepping up or stepping down the A.C. voltage
(b) Stabilizer	(ii) Used to convert A.C. voltage into D.C. voltage
(c) Transformer	(iii) Used to remove any ripple in the rectified output voltage
(d) Filter	(iv) Used for constant output voltage even when the input voltage or load current change

Q.

Explain why does a metal wire when connected to a cell offer resistance to the flow of current.

Q.

A rheostat is used in an electrical circuit

1. To change the e.m.f

2. To change the current through the particular instrument

3. To change the resistance of the circuit

4. To change the potential difference

Q.

The resistance of alloys decreases with the increase in temperature.

1. True

2. False

Q.

Resistance of a conductor depends upon.

Q.

The transformation ratio of a step-up transformer is

1. 1

2. Greater than 1

3. Less than 1

4. The ratio greater or less than depends on 1 on other factors

Q.

When A $40\mathrm{V}$ battery is connected across an unknown resistor, There is a current Of $100\mathrm{mA}$ In the circuit. Find the value of the resistance of the Resister?

1. $5000\Omega$

2. $800\Omega$

3. $0.8\Omega$

4. None Of These

Q.

The property of a conductor which it opposes the flow of current is known as?

Q.

In the figure, the steady-state current through the inductor will be:

Q.

__________ is the property by which a material hinders the flow of electrons

1. Voltage

2. Current

3. Power

4. Resistance

Q.

What is the cause of resistance in wires?

1. Collision of electrons

2. Due to presence of neutrons

3. None of the above

4. Collision of protons with protons

Q.

How does the balancing length change if the length of the potentiometer wire is doubled?