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The terminal voltage of a battery is less than its electromotive force (emf) due to internal resistance within the battery. When a load is connected, current flows, causing a voltage drop across this internal resistance, which reduces the voltage available at the terminals. This phenomenon is particularly noticeable under high load conditions, where the current is greater, leading to a more significant drop. Thus, the terminal voltage reflects the actual voltage available to the external circuit, which is always less than the emf when current is drawn.
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What the counter emf of a motor is always less than applied armature voltage.explain?
The counter electromotive force (counter EMF) of a motor is always less than the applied armature voltage because the motor requires a certain amount of voltage to overcome its internal resistances and inductances, as well as to produce torque. When the motor starts, the armature current is high, leading to a significant voltage drop due to resistance. As the motor speeds up, the counter EMF increases, but it never reaches or exceeds the applied voltage, as some voltage is always required to maintain current flow and overcome losses like friction and heat. Thus, the counter EMF is always a fraction of the applied voltage.
What is the formula for armature resistance of shunt excited DC generator?
The armature resistance of a shunt excited DC generator is calculated using the formula ( R_a = \frac{V - E}{I_a} ), where ( R_a ) is the armature resistance, ( V ) is the terminal voltage, ( E ) is the generated EMF (electromotive force), and ( I_a ) is the armature current. The difference between the terminal voltage and the generated EMF accounts for the voltage drop across the armature resistance due to the current flowing through it.
How does voltage drop related to impressed emf?
Voltage drop is resultant of IR ie current and the line resistance, not dependent on impressed emf
Difference between back EMF and induced EMF?
An induced electromotive force (emf) is an induced voltage. Voltage (emf) causes current flow, and this induced voltage will cause a current that is called the induced current.We might also add that the induced current will cause a magnetic field to expand about the current path, and this field will "sweep" the conductor. The sweeping of the conductor by that expanding magnetic field will set up an emf that will oppose the emf that was creating it.CommentTechnically, there is no such thing as an 'induced current'. It is voltage that is induced. Any current flows as a result of that induced voltage being applied to a load. But that current is certainly NOT induced!
Why do you measure emf with a potentiometer not with voltmeter?
EMF (E''electromotive Force'') is another term for Volts, hence the E in electronic formulas and EMF is measured with a volt meter. A potentiometer is not a meter at all, it is a variable resistor
Can the terminal voltage of a battery be larger than its emf?
the voltage of a battery could be larger than the emf if you are to charge the battery, in that case V=E+Ir .
Can terminal potential difference be greater than the emf supplied?
No, the terminal potential difference cannot be greater than the emf supplied. The emf represents the maximum potential difference that the cell or battery can provide, while the terminal potential difference is the actual potential difference across the terminals when a load is connected.
What is the Condition for terminal voltage across a secondary cell to be equal to its emf?
The condition for the terminal voltage across a secondary cell to be equal to its emf is when there is no current flowing through the cell. When there is no current, there is no voltage drop across the internal resistance of the cell, and thus the terminal voltage equals the emf.
How do you connect a voltmeter to a battery?
To measure the total emf simply connect the battery and voltmeter with the right terminals , but to measure the terminal potential difference which is less than the emf the voltmeter is connected in parallel with the battery
What the counter emf of a motor is always less than applied armature voltage.explain?
The counter electromotive force (counter EMF) of a motor is always less than the applied armature voltage because the motor requires a certain amount of voltage to overcome its internal resistances and inductances, as well as to produce torque. When the motor starts, the armature current is high, leading to a significant voltage drop due to resistance. As the motor speeds up, the counter EMF increases, but it never reaches or exceeds the applied voltage, as some voltage is always required to maintain current flow and overcome losses like friction and heat. Thus, the counter EMF is always a fraction of the applied voltage.
Why emf of battery driving potentiometer is greater than emf of the cell to be measured?
Bcoz the emf which is to be measured is less than emf of driving cell....
What are the differences between emf and voltage drop?
emf and voltageAnswerElectromotive force is the potential difference created by a source, such as a battery or generator, when it is not connected to a load -in other words, on 'open circuit'.Voltage drop is the potential difference across a load, such as a resistor, which causes current to flow through that load.A voltage drop occurs, internally, in batteries and generators, when they are supplying a load. The battery or generator's terminal voltage, when supplying a load, is its e.m.f. less its internal voltage drop.
When is the terminal potential difference of a battery greater than its emf?
When it is being loaded.
Is emf current greater than current?
EMF is electromotive force. It is another name for voltage. Voltage is electric potential in joules per coulomb. Current is electric flow, in amperes. Amperes are coulombs per second. Voltage and current are not the same thing, and "emf current", or "voltage current" does not make sense.
Is potential difference always less than emf of the cell?
No. Because during charging process of a battery current flows in opposite direction to the discharging/consumption. so equation Emf=P.d. +Ir is changed to Emf=p.d. +Ir. Hence during charging process of a battery Potential difference is greater than electromotive force.
If A generator has an armature resistance of 0.6 ohms and when connected to a load of 40.9 ohms passes a current of 3.5 A what is the terminal voltage and generated EMF?
145.25 v
What is the formula for armature resistance of shunt excited DC generator?
The armature resistance of a shunt excited DC generator is calculated using the formula ( R_a = \frac{V - E}{I_a} ), where ( R_a ) is the armature resistance, ( V ) is the terminal voltage, ( E ) is the generated EMF (electromotive force), and ( I_a ) is the armature current. The difference between the terminal voltage and the generated EMF accounts for the voltage drop across the armature resistance due to the current flowing through it.
