Resistors Network Balancing and Meter Bridge Quiz

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Questions and Answers

What is Kirchhoff's second law based on?

Conservation of energy

To minimize the error due to contact resistance in a meter bridge, what should be done?

Interchanging the position of known and unknown resistances

What is the SI unit of potential gradient?

V/m

Which instrument can measure terminal potential difference as well as electromotive force?

Potentiometer Signup and view all the answers

When the null point is obtained in a potentiometer, where is the current drawn from?

Main battery Signup and view all the answers

If the potential gradient of a wire decreases, what happens to its length?

Increases Signup and view all the answers

What is the percentage error in the voltmeter reading when it balances at 350 cm with a reading of 1.8V, given that the standard cell's emf is 1.5V and was balanced at 300 cm?

2.8571% Signup and view all the answers

How would you determine the internal resistance of a cell using a potentiometer?

By finding the ratio of potential differences across the cell and the potentiometer wire. Signup and view all the answers

Why is a potentiometer preferred over a voltmeter for measuring emf?

Potentiometer provides more accurate and direct readings. Signup and view all the answers

In the right hand rule, what is the direction of magnetic induction if the current flows in an anticlockwise direction?

Perpendicular and outwards Signup and view all the answers

For a conductor with two straight segments of length L and a semicircular segment with radius R carrying a current I, what is the magnetic field at point P?

(a) Signup and view all the answers

What happens to a stationary electron when exposed to a strong magnetic field?

The electron starts moving in circles. Signup and view all the answers

What is the resistance needed to be connected in series with a galvanometer to convert it into a voltmeter of range 4Vm?

$3Vm$ Signup and view all the answers

In a meter bridge experiment, what happens if the balance point is found at 30 cm from the end A when the resistor R is 15 Ω (right gap)?

Resistance of X is 15 Ω (left gap). Signup and view all the answers

How can errors in a meter bridge experiment be minimized?

By ensuring good connections and avoiding parallax errors. Signup and view all the answers

What should be the resistance introduced in the resistance box to achieve a potential drop of one microvolt per cm in a potentiometer wire?

$5 \times 10^{4} \Omega$ Signup and view all the answers

When comparing the emf's of two cells using a potentiometer by connecting them individually, what does the balance point indicate?

Equal emf's of both cells. Signup and view all the answers

If a cell with an e.m.f of 2V and internal resistance of 0.5Ω is connected in series with another cell, what would be the effect on overall voltage and internal resistance?

Increase in overall voltage, increase in internal resistance. Signup and view all the answers

Study Notes

Resistance and Meter Bridge

To balance a network, a 9 Ω resistance is connected across the 18 Ω resistance.
A galvanometer of resistance G can measure a maximum safe voltage of Vm.
To convert a galvanometer into a voltmeter of range nVm, a resistance of (n-1) G should be connected in series.

Meter Bridge Experiment

A meter bridge is used to determine unknown resistances.
A neat circuit diagram is required to explain the process.
Errors in the meter bridge experiment can occur due to:
- Contact resistance
- Gap resistance
These errors can be minimized by:
- Interchanging the position of known and unknown resistances
- Using a uniform wire

Potential Gradient

Potential gradient is measured in V/m.
It is measured using a potentiometer.
A potentiometer is used to compare the emf's of two cells by connecting the cells individually.

Potentiometer

A potentiometer is used to measure the emf of a cell.
It can be used to compare the emf's of two cells by connecting the cells individually or by the combination method.
The internal resistance of a cell can be determined using a potentiometer.
The formula for internal resistance can be derived using a potentiometer.

Magnetic Effect of Electric Current

According to the right-hand rule, the direction of magnetic induction is perpendicular and outwards if the current is directed in an anticlockwise direction.
The magnetic field B at point P can be calculated using the formula B = (μ₀ * I) / (4 * π * R).

Capacitance and Electric Potential

The capacitance of a parallel plate capacitor with a dielectric slab between the plates can be calculated using the formula C = (ε₀ * εr * A) / d.
The electric potential due to an electric dipole can be derived using the formula V = (p * cosθ) / (4 * π * ε₀ * r²).

Current Electricity

Kirchhoff's second law (voltage law) is based on the conservation of energy.
The error due to contact resistance in the meter bridge experiment can be minimized by interchanging the position of known and unknown resistances.
The SI unit of potential gradient is V/m.
A potentiometer can measure terminal potential difference as well as electromotive force (emf).
When null point is obtained in the potentiometer, the current is drawn from the main battery.
If the potential gradient of a wire decreases, its length increases.

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