UPPCL JE key terms

The rule stating that a changing magnetic flux through a coil induces an EMF proportional to the rate of change of that flux. It underlies transformers, generators and inductors, and its direction is fixed by Lenz's law.

A consequence of energy conservation stating that an induced current flows in a direction whose magnetic effect opposes the change producing it. It gives the negative sign in Faraday's law and explains the opposing torque in motors.

The property of a coil by which a change in its own current induces an EMF in it, measured in henries. It depends on turns squared, core permeability and geometry, and opposes sudden current changes.

The voltage induced in a running motor's armature that opposes the applied supply voltage. It limits armature current, so a motor draws a large starting current before the armature speeds up.

The cosine of the phase angle between voltage and current in an AC circuit, equal to real power divided by apparent power. A low value means more current for the same useful power, raising losses and billing penalties.

The oscillating power exchanged between source and reactive elements such as inductors and capacitors, measured in volt-amperes reactive. It does no net work but is needed to build magnetic fields in motors and transformers.

The product of RMS voltage and RMS current in an AC circuit, measured in volt-amperes. It combines real and reactive power as the hypotenuse of the power triangle.

A winding arrangement joining three phase ends at a common neutral point. Line voltage equals root-three times phase voltage while line current equals phase current, making it suitable for high-voltage transmission and distribution.

A three-phase winding arrangement connected end to end in a closed loop. Line current equals root-three times phase current while line voltage equals phase voltage, commonly used for motor windings and distribution transformers.

The relation giving induced EMF per turn as 4.44 times frequency times peak flux, so total EMF is 4.44 f N flux-max. It shows that for fixed voltage and frequency, core flux is constant regardless of load.

The ratio of primary to secondary turns of a transformer, which equals the voltage ratio and the inverse of the current ratio. It sets whether the transformer steps voltage up or down.

The constant loss in a transformer's magnetic core, made of hysteresis and eddy-current components. It depends on voltage and frequency rather than load, and is measured by the open-circuit test.

The resistive I-squared-R heating in transformer or machine windings, varying with the square of load current. It is measured by the short-circuit test and is maximum at full load.

The fractional difference between synchronous speed and actual rotor speed, usually a few percent at full load. Slip must be nonzero for the rotor to develop torque, and it rises with mechanical loading.

The rotating field speed of a machine, equal to 120 times frequency divided by number of poles. A four-pole machine on 50 Hz supply runs at 1500 rpm, and induction rotors always run slightly slower.

The torque an electric motor develops at zero speed when switched on. It must exceed the load torque for the drive to accelerate, and methods such as star-delta starting trade reduced starting current for lower torque.

Deliberate connection of exposed metalwork or a circuit neutral to earth so fault current returns safely and protective devices trip. It limits touch voltage and is mandatory for consumer installations under safety rules.

A protective device containing a metal element that melts and opens the circuit when current exceeds its rating for a set time. Its inverse time-current characteristic protects cables but must be replaced after operation.

A resettable switch that automatically opens on overload or short circuit using thermal or magnetic tripping. Unlike a fuse it can be reclosed, and its rated breaking capacity must exceed prospective fault current.

The principle that the algebraic sum of currents entering a node is zero, because charge cannot accumulate at a junction. It is used with Kirchhoff's voltage law to solve multi-loop networks.

A network reduction method replacing any linear two-terminal circuit by an equivalent voltage source in series with a resistance. It simplifies load-current calculations and is widely used in circuit analysis problems.

The relation stating that current through a conductor is directly proportional to voltage across it and inversely proportional to resistance, at constant temperature. It applies to linear elements only.

The difference between sending-end and receiving-end voltage caused by line resistance and reactance carrying load current. It is reduced by higher transmission voltage or by compensating reactive power.

The supreme law of the country, adopted in 1949 and effective 26 January 1950, setting out fundamental rights, directive principles and the structure of government. It is the longest written national constitution.

Guarantees in Part III of the Constitution, such as equality, freedom of speech, and protection of life and personal liberty, enforceable through writs in the Supreme Court and High Courts.

The opening statement of the Constitution declaring India a sovereign, socialist, secular, democratic republic and listing justice, liberty, equality and fraternity as its objectives. It was amended once, in 1976.

Actions by the Reserve Bank of India to manage money supply and inflation, mainly through the repo rate, reverse repo, cash reserve ratio and open market operations. The Monetary Policy Committee sets the policy repo rate.

The interest rate at which the Reserve Bank of India lends short-term funds to commercial banks against government securities. Raising it tightens liquidity and is used to control inflation.

A sustained rise in the general price level that reduces the purchasing power of money. In India it is commonly tracked by the Consumer Price Index, and central banks respond by tightening monetary policy.

A form of deductive reasoning with two premises and a conclusion, tested by checking whether the conclusion necessarily follows. Questions often ask which conclusions definitely hold given the statements.

A technique of drawing circles to represent sets and their overlaps so that valid conclusions in syllogism or set problems can be checked visually. It quickly reveals possibilities that break a proposed conclusion.

A reasoning question type giving a short statement followed by conclusions, of which only those following logically from the statement are to be selected. Outside knowledge must be ignored unless stated.

A puzzle requiring candidates to place people around a circle or in a row using clues about relative positions, facing direction and neighbours. Drawing a rough layout and marking fixed positions speeds solution.

A reasoning topic where relationships among family members are described in coded or indirect language and the candidate must identify a specific relation. Drawing a family tree with symbols avoids confusion.

A question type in which words or numbers are written in a coded pattern and the candidate must apply the same rule to a new word or decode it. Letter shifts, reversals and position values are common rules.

दो वर्णों के मेल से उत्पन्न विकार को संधि कहते हैं, जैसे विद्या + आलय = विद्यालय। स्वर संधि, व्यंजन संधि और विसर्ग संधि इसके तीन प्रमुख भेद हैं।

दो या अधिक शब्दों के मेल से बने संक्षिप्त पद को समास कहते हैं, जैसे राजपुत्र = राजा का पुत्र। तत्पुरुष, कर्मधारय, द्विगु, द्वंद्व, बहुव्रीहि और अव्ययीभाव इसके भेद हैं।

वह शब्दांश जो किसी शब्द के आरंभ में जुड़कर उसके अर्थ में परिवर्तन या विशेषता लाता है, जैसे प्र + हार = प्रहार। हिंदी में संस्कृत, हिंदी और उर्दू के उपसर्ग प्रचलित हैं।

A sentence construction in which the subject performs the action, as in the engineer tested the relay. It is usually clearer and more direct, and is the base form used when converting to passive voice.

A construction in which the object of the action becomes the subject, formed with a form of be plus past participle, as in the relay was tested. It is used when the doer is unknown or unimportant.

Reporting a speaker's exact words inside quotation marks, as in She said, I will attend. Converting it to indirect speech requires back-shifting tenses and adjusting pronouns and time words.

Volatile primary memory that stores programs and data currently in use and allows any location to be read or written quickly. Its contents are lost when power is switched off.

Non-volatile memory whose contents are retained without power and normally cannot be rewritten during operation. It stores firmware such as the BIOS used to start a computer.

A small, very fast memory placed between the processor and main memory that holds recently used instructions and data. It reduces average access time and improves CPU performance.

A unique numerical label assigned to a device on a network so data can be routed to it. IPv4 uses 32-bit addresses written as four decimal octets, while IPv6 uses 128 bits.

A network covering a limited area such as an office or building, connecting computers and printers at high speed. It may be wired via Ethernet or wireless via Wi-Fi.

System software that manages hardware, files, memory and processes and provides a user interface, examples being Windows, Linux and Android. Application programs rely on it for all resource access.