Can voltmeter measure emf accurately?
Voltmeter does not measure emf but it measures potential difference.
Which instrument measures emf of a cell most accurately?
potentiometer
answer is potentiometer. as a voltmeter draws some current in cell it can not givethe accurate rating. a potentiometer is the best option as during the measurement by potentiometer no current flows through it.
What device measures emf of a cell?
A potentiometer is a device mainly used to measure the emf of a given cell and to compare emf’s of cells.
Why voltmeter reading is different from the battery emf?
Explain why this is so. The reading on the voltmeter gives the potential difference across the external circuit. When a current flows some of the EMF is used to drive that current through the battery . This results in voltage being ‘lost’ across the internal resistance as this is not measured on the instrument.
Why potentiometer is better than voltmeter?
The potentiometer is preferred over voltmeter when there is a measurement of emf of the cell because the potentiometer does not draw any current as it is a null device. Whereas voltmeter draws current from the cell.
Can a voltmeter measure current?
A voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. Portable instruments, usually equipped to also measure current and resistance in the form of a multimeter, are standard test instruments used in electrical and electronics work.
How can we measure EMF?
The EMF of the cell can be determined by measuring the voltage across the cell using a voltmeter and the current in the circuit using an ammeter for various resistances. We can then set up a circuit to determine EMF as shown below.
Why multimeter or voltmeter does not give more accurate reading of voltage?
Answer: Voltmeter is accurate for voltage and ammeter is accurate for current measurement. This is because a high current of the order of few hundreds or thousand amperes cannot be taken directly by any ammeter. The current , sometimes for calibration, is generated by low voltage of 2.5 V or even lower.
Which of the following device is used to measure EMF of different types of cells voltmeter barometer thermometer galvanometer?
Explanation: A potentiometer is an instrument which is used to measure E.m.f. Of different types of cells.
Why is voltmeter reading less than EMF?
Explain without calculation, why the voltmeter reading is less than the EMF of the battery. The battery has internal resistance. When a current passes through the circuit work is done (or voltage is used) to drive the current through the battery itself which reduces the value of the open circuit voltmeter reading.
Why is a potentiometer preferred over a voltmeter to measure emf?
How do you measure the emf of a cell?
Ok, Emf is the voltage in a cell when no current flows through the circuit. Then how do we measure it? If one says that connect the cell (of unknown emf) having some finite internal resistance with the voltmeter (assume it is ideal) in parallel and u will get the emf of the cell.
Is it possible to measure EMF with an ideal voltmeter?
So your teacher is right in saying that with an ideal voltmeter we cannot measure EMF of a cell. But in real life since nothing is ideal turns out we can measure with an ordinary voltmeter.
Why is a potentiometer used to measure a cell’s EMF?
To measure a cell’s emf a potentiometer is used since in a potentiometer measurement no current is flowing. It employs a null method of measuring potential difference, so that when a balance is reached and the reading is being taken, no current is drawn from the source to be measured.
Why can’t a voltmeter be used to measure the terminal voltage?
The terminal voltage of a cell is the potential difference between its electrodes. A voltmeter cannot be used to measure the emf of a cell because a voltmeter draws some current from the cell. To measure a cell’s emf a potentiometer is used since in a potentiometer measurement no current is flowing.