Untitled Quiz

<p>The voltmeter measures the total voltage including the ammeter (A)</p> Signup and view all the answers

<p>Ammeter-Voltmeter method (D)</p> Signup and view all the answers

<p>From 1 Q to about 0.1 MQ (A)</p> Signup and view all the answers

<p>Disturbances in circuit conditions (D)</p> Signup and view all the answers

<p>To determine the difference between standard and unknown resistances (C)</p> Signup and view all the answers

<p>The difference in length between two positions at balance (D)</p> Signup and view all the answers

<p>S - R = (l1 - l2)r (A)</p> Signup and view all the answers

<p>So their ratio is equal to the ratio of R to S (A)</p> Signup and view all the answers

<p>The resistances of P and Q contact resistances and connecting leads (A)</p> Signup and view all the answers

<p>86 Ω (A)</p> Signup and view all the answers

<p>1.19% (A)</p> Signup and view all the answers

<p>Using their standard deviations in a formula (B)</p> Signup and view all the answers

<p>(0.25 / 35.5) x 100 (A)</p> Signup and view all the answers

<p>A combination of both R and S with an ammeter (C)</p> Signup and view all the answers

<p>(0.5/35.5)x100 (B)</p> Signup and view all the answers

<p>± 1.38% (C)</p> Signup and view all the answers

<p>Resistance of the ammeter (A)</p> Signup and view all the answers

<p>S is inserted into the circuit (A)</p> Signup and view all the answers

<p>3% to 5% (B)</p> Signup and view all the answers

<p>No current flows through the galvanometer. (A)</p> Signup and view all the answers

<p>A galvanometer (D)</p> Signup and view all the answers

<p>To provide a known reference resistance. (C)</p> Signup and view all the answers

<p>It is inversely proportional to the total resistance. (D)</p> Signup and view all the answers

<p>The circuit's battery emf constancy. (C)</p> Signup and view all the answers

<p>It allows direct comparison of unknown and known resistances. (B)</p> Signup and view all the answers

<p>The sensitivity of the instrument. (D)</p> Signup and view all the answers

<p>A modified Wheatstone bridge. (D)</p> Signup and view all the answers

<p>It indicates the balance of potentials at the bridge. (C)</p> Signup and view all the answers

<p>Sensitivity decreases considerably. (A)</p> Signup and view all the answers

<p>An emf and an internal resistance. (B)</p> Signup and view all the answers

<p>R = S = P = Q (A)</p> Signup and view all the answers

<p>It doubles the sensitivity of the bridge. (A)</p> Signup and view all the answers

<p>The Thevenin equivalent circuit. (A)</p> Signup and view all the answers

<p>It reduces accuracy. (C)</p> Signup and view all the answers

<p>$£Un = E - En$ (B)</p> Signup and view all the answers

<p>Increased sensitivity leads to decreased accuracy. (B)</p> Signup and view all the answers

<p>It affects the deflection observed. (A)</p> Signup and view all the answers

<p>Sensitivity will decrease considerably. (B)</p> Signup and view all the answers

Resistances of the order of 0.1 megaohms or higher.

Resistances from 1 ohm upwards to about 0.1 megaohms.

Resistances of the order of 1 ohm or lower.

A method to measure resistance using an ammeter and a voltmeter.

The ammeter measures the true current but the voltmeter measures the total voltage including the voltage drop across the ammeter itself.

A method to find resistance by replacing the unknown resistor with a known one and adjusting until the same current flows.

The Wheatstone bridge is a precise circuit used to measure unknown resistances.

The difference between the measured value and the true value of a quantity, expressed as a percentage of the true value.

The resistance of a component measured directly using a voltmeter and ammeter.

The actual or true value of a resistance, often determined using a more precise method.

A method to calculate the overall error in a measurement by combining the individual errors of each component.

A type of resistance that has a variable value, allowing you to adjust the amount of resistance in a circuit.

The difference between the true value and the value measured in the experiment.

The process of determining how much or how often something is being measured, including the precision and accuracy of the measurement.

The accuracy of a resistance measurement depends on factors like the stability of the battery's voltage, the resistance of the circuit excluding the unknown resistance, the sensitivity of the measuring instrument, and the accuracy of the standard resistance used.

In a Wheatstone bridge, the points where the bridge is believed to be balanced are called ‘c' and ‘d'. The potential difference between these points determines the current flow through the galvanometer.

When no current flows through the galvanometer in a Wheatstone bridge, indicating a balanced state, this happens when the potential difference between points 'c' and 'd' is zero.

The voltage drop across the standard resistor (P) is equal to the voltage drop across the unknown resistor (R) when the Wheatstone bridge is balanced. This relationship is based on the current and the resistance values.

The Wheatstone bridge is a common and accurate method for measuring medium resistances, offering much higher precision compared to other methods like the standard ohmmeter.

The sensitivity of the galvanometer is a crucial factor in the Wheatstone bridge's accuracy: a more sensitive galvanometer can detect even smaller current variations, leading to more precise measurements.

The substitution method, despite its simplicity, is a valuable technique used in various applications like bridge methods and high-frequency AC measurements. Its core principle involves comparing known and unknown quantities to determine the unknown.

The Wheatstone bridge is a circuit with four resistive arms (P, Q, R, and S). A battery provides the power source, and a galvanometer acts as a null detector to determine balance.

A method used to compare two nearly equal resistances by adjusting the position of a sliding contact on a slide-wire to achieve balance.

The point at which the current through the galvanometer in a bridge circuit is zero, signifying that the voltage across the bridge is equal.

The ratio of the resistance per unit length of the slide-wire to the difference in lengths at balance.

The process of determining the resistance per unit length of the slide-wire by shunting a known resistance and measuring the change in balance length.

A known resistance used for comparison with an unknown resistance in a bridge circuit.

The sensitivity of a Wheatstone bridge decreases significantly when the ratio of resistances (P/Q and R/S) deviates from unity (1). This means the bridge becomes less responsive to changes in the unknown resistance.

A Thevenin equivalent circuit simplifies a complex circuit into a voltage source (emf) and an internal resistance. This allows for easier analysis of the current flowing through the galvanometer in a Wheatstone bridge.

The open-circuit voltage between terminals b and d in a Wheatstone bridge, measured when the galvanometer circuit is open. It represents the potential difference that drives the current through the galvanometer.

The internal resistance of the Thevenin equivalent circuit of a Wheatstone bridge. It represents the resistance encountered by the galvanometer current.

The current flowing through the galvanometer in a Wheatstone bridge. This current is directly proportional to the imbalance in the bridge and helps determine the unknown resistance.

A method to eliminate the effects of thermo-electric emfs in resistance measurements. This is done by taking two readings with the current direction reversed and averaging the results.

The sensitivity of a Wheatstone bridge can be doubled by using the current reversal method. This is because the errors from thermo-electric emfs are effectively removed, allowing for a more precise measurement.

Temperature changes can affect the resistance values in the Wheatstone bridge, influencing the accuracy of the measurement. It's crucial to minimize temperature variations during the measurement.

In a Wheatstone bridge with perfectly balanced arms (R=S=P=Q), the sensitivity of the bridge is maximized. This means even small changes in resistance are easily detectable.