1 Answer

Answer :

It is required to measure the true open circuit e.m.f. of a battery. The best device is D.C. potentiometer.

Related questions

Description : An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be  (1) unaffected (2) decreased (3) increased (4) either decreased or increased depending on the direction of the DC field

Last Answer : An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be either decreased or increased depending on the direction of the DC field

Description : Describe the difference between an open circuit and a short circuit.

Last Answer : Open circuit means the wire is cut meaning power will not flow and close circuit means wire is not cut and hence power will flow.Short circuit is the same as close circuit

Description : A d.c. source has an open circuit voltage of 30 V and an internal resistance of 1.5 Ohm. A resistive load is connected to the source. Maximum power dissipated in the load is (A) 300 W (B) 150 W (C) 45 W (D) 20 W

Last Answer : A d.c. source has an open circuit voltage of 30 V and an internal resistance of 1.5 Ohm. A resistive load is connected to the source. Maximum power dissipated in the load is 150 W

Description : During open circuit test of a transformer?

Last Answer : During open circuit test of a transformer primary is supplied rated voltage.

Description : Explain open emitter BJT drive circuit.

Last Answer : open emitter BJT drive circuit:

Last Answer : Primary side is low voltage side and secondary side is high voltage side.

Description : Draw the circuit diagram of battery charger using SCR and explain it’s working.

Last Answer : Battery charger circuit using SCR: The figure shows the battery charger circuit using SCR. A 12V discharged battery is connected in the circuit and switch SW is closed. The singlephase 230V ... not fired. In this way, after full charging, further charging is automatically stopped.

Last Answer : E.m.f. of a Weston cell is accurately measured by electrostatic voltmeter.

Description : A Pyrheliometer is an instrument to measure :  (A) temperature of solar photovoltaic cell  (B) intensity of direct solar radiation at normal incidence  (C) intensity of indirect solar radiation  (D) efficiency of a solar photovoltaic cell

Last Answer : A Pyrheliometer is an instrument to measure : intensity of direct solar radiation at normal incidence 

Description : Piezoelectric Transducer is used to measure  (1) displacement (2) resistance (3) current (4) temperature

Last Answer : Piezoelectric Transducer is used to measure displacement 

Description : Which of the following can be used to measure the capacitance of a capacitor? A) Rheostat B) Schering bridge C) Wheatstone bridge D) None of these

Last Answer : Which of the following can be used to measure the capacitance of a capacitor? A) Rheostat B) Schering bridge C) Wheatstone bridge D) None of these

Last Answer : To measure a resistance with the help of a potentiometer it is not necessary to standardise the potentiometer.

Last Answer : Integrating instruments are those which measure the total quantity of electricity delivered in a particular time.

Description : What is the unit of measure for voltage?

Last Answer : Voltage measured in volts.

Description : What type of meter is used to measure current?

Last Answer : Ammeter

Description : What equipment is used to measure voltage?

Last Answer : Voltmeter is used to measure voltage.

Last Answer : Yes it can...

Last Answer : Voltmeter is used to measure voltage in a circuit.Ohmmeter is used to measure the resistance of a component in a circuit.

Description : An open-circuit test on a transformer is conducted primarily to measure?

Last Answer : The open-circuit test in a transformer is used to measure

Description : The counter e.m.f. of a d.c. motor?

Last Answer : The counter e.m.f. of a d.c. motor helps in energy conversion.

Last Answer : If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by Blv.

Last Answer : When the armature of a D.C. motor rotates, e.m.f. induced is back e.m.f.

Last Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.

Last Answer : In case of D.C. shunt motors the speed is dependent on back e.m.f. only because flux is practically constant in D:C. shunt motors.

Last Answer : The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.

Description : How to Measure Optical Distortion

Last Answer : How to Measure Optical Distortion Optical Distortion is defined as a defect in an optical system. In this defect, the magnification of lines causes lines that are typically straight and sitting at an ... to measure optical illusions and also how the illusion is affecting the way you see a specimen.

Description : How to Measure a Strain Gauge

Last Answer : How to Measure a Strain Gauge There are several ways to measure strain. The most common is to use a strain gauge. In laymen's terms, a strain gauge is a device whose electrical ... who supply all the necessary strain gauges and materials from connection tags, to binding adhesives and training.

Description : How to Read a Tape Measure

Last Answer : How to Read a Tape Measure Introduction Reading a tape measure is fairly simple. At some point, you may need to learn this method. Everyone is presented with the need for this device at one time or ... hand. Take extra care and check the measurement 2 or 3 times to be sure that they are correct.

Description : How to Measure Temperature

Last Answer : How to Measure Temperature Whether you're measuring body temperature or dealing with high-temperature substances in laboratories, you need a very reliable way to measure heat. Thermometers and temperature ... or from an object. With these steps, you can measure temperature quickly and accurately.

Description : How to Measure For Replacement Windows

Last Answer : How to Measure For Replacement Windows You could have any number of reasons for wanting to replace your windows. Windows that are older are often far less energy efficient than the newer vinyl ... probably even give you a rebate for choosing energy efficient windows to replace your old windows.

Description : How to Measure For a Garage Door

Last Answer : How to Measure For a Garage Door At some point you will probably need a new garage door. Before getting the new door, however, you will need to take some measurements. This article explains how to measure ... a new garage door you needn't worry if the garage door you buy will fit into the opening.

Description : How to Measure Tire Sizes

Last Answer : How to Measure Tire Sizes Buying a new set of tires is just like buying shoes: you have to make sure that your tires fit perfectly on the wheel. Tires that are too small or too big for your ... , you can buy a set of tires designed and custom-fit to make your driving experience safe and secure.

Description : Draw venture meter and write steps to measure flow rate.

Last Answer : Venturi meter consists of three sections that is converging section, throat section and diverging section. The flow is introduced to the meter through the inlet with diameter D' . The inclined angle ... to 15o . Flow rate is proportional to the square root of the differential pressure.

Description : Explain the term reactive power. Why it is sometimes essential to measure reactive power?

Last Answer : Reactive power: The reactive power (Q) is defined as the product of voltage(V), current (I) and sine of angle between voltage(V) and current( I) Therefore Reactive power Q = V I ... power so that corrective measures can be taken accordingly to maintain systems power factor near to the unity.

Description : List any four measure knobs on front panel on CRO.

Last Answer : Knobs on front panel of CRO: 1. Power ON- OFF 2. Intensity control 3. Focus control 4. Astigmatism control 5. Volt/Div control 6. Vertical position control 7. Invert 8. Horizontal position control 9. Synchronization. 10. Channel selection.

Description : ‘PMMC instrument is not suitable to measure AC quantity’. State the reason.

Last Answer : The direction of force exerted on moving coil depends on the direction of current flowing through moving coil. If the direction of magnetic field is kept constant, it produces unidirectional torque if the current is ... on the coil in one cycle to zero. Hence the meter cannot read A.C. quantities.

Description : Name the method used to measure following resistances:- (i) Low resistance (ii) Medium resistance (iii) Insulation resistance (iv) Earth resistance.

Last Answer : Following are the methods used to measure resistances:-  (i) Low resistance: 1.Voltmeter-Ammeter Method 2. Kelvin's Double bridge Method  (ii) Medium resistance: 1.Voltmeter-Ammeter Method 2. ... of Charge Method  (iv) Earth resistance : 1. Fall of Potential Method 2. Earth tester

Description : A _________ is used to measure the stator % winding temperature of the generator.  (A) Thermocouple (B) Pyrometer (C) Resistance thermometer (D) Thermometer

Last Answer : A Resistance thermometer is used to measure the stator % winding temperature of the generator. 

Description : How do you measure power factor?

Last Answer : P= 1.83*V*I*COS@ where P is power           V is voltage            I is current           COS @ is P.F COS@= P/(1.83*V*I)  in other way cos @ = true power/apparent power

Description : How to Open a Tight Jar Lid

Last Answer : How to Open a Tight Jar Lid There are instances when you buy a stubborn jar of pickles (Learn how to pickle), peanut butter or mayonnaise that you can't open with your hands. It can drive you ... no time. If you enjoy reading this article, you might as well read how to can fruits and vegetables.

Description : How to Open a Can without a Can Opener

Last Answer : How to Open a Can without a Can Opener You're dying to sink your teeth into those canned peaches, but you find yourself without any can opener. At times like this, many people would easily give up ... you'll soon find yourself enjoying the yummy contents of the can. Be careful not to spill the food!

Description : Open-Face Shrimp Melt

Last Answer : Open-Face Shrimp Melt - serves 2 Preparation - 15 minutes 3 ounces shelled and deveined cooked small shrimp, cut lengthwise into halves 1/4 cup chopped celery 2 tbsp chopped scallion (green ... baking sheet arrange sandwiches and broil 6 inches from heat source until cheese melts, about 1 minute.

Description : What are the disadvantages of Open loop control system?

Last Answer : Open loop control system are less reliable. In open loop control system Optimization is not possible. Open loop control system are less accurate.

Description : Why CT is never operated with an open secondary ?

Last Answer : CT secondary should never be kept open because it will cause saturation of the core to a high level and very high voltage will appear across the secondary which can breakdown the insulation. One terminal of PT secondary is always grounded to avoid capacitive induction and for human safety

Description : What will happen to the gain margin if the gain of the open loop system is doubled? A) Doubled B) Becomes half C) Is not affected D) Becomes one-fourth 

Last Answer : What will happen to the gain margin if the gain of the open loop system is doubled? A) Doubled B) Becomes half C) Is not affected D) Becomes one-fourth 

Description : If the gain of the open loop system is doubled, the gain margin  (1) Is not affected (2) Gets doubled (3) Becomes half (4) Becomes one -forth

Last Answer : If the gain of the open loop system is doubled, the gain margin Becomes half

Description : An open resistor, when checked with an ohm-meter reads?

Last Answer : An open resistor, when checked with an ohm-meter reads infinite.

Last Answer : Open circuited armature coil of a D.C. machine is identified by the scarring of the commutator segment to which open circuited coil is connected and indicated by a spark completely around the commutator.

Last Answer : If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will stop.