**Description :** If resistance is 8 Ohm and current is 16 ampere then what will be the voltage and power?

**Last Answer :** 128 volts ,2048 watts

**Description :** A d.c. voltage of 230 V is imposed on an unloaded 230 V, 50 Hz transformer, it will (A) give high secondary voltage (B) burn out (C) give secondary voltage as per k (D) None of these

**Last Answer :** A d.c. voltage of 230 V is imposed on an unloaded 230 V, 50 Hz transformer, it will burn out

**Description :** A single phase 230 V/ 150 V , 1 kVA, 50 Hz transformer is supplied by 230 V AC supply. Find the full load primary and secondary current.

**Description :** Sinusoids find amplitude, period, frequency, voltage (Problem 1)

**Last Answer :** Sinusoids find amplitude, period, frequency, voltage (Problem 1)

**Description :** The low voltage winding of a 400/230 V, 1-phase, 50 Hz transformer is to be connected to a 25 Hz, the supply voltage should be

**Last Answer :** The low voltage winding of a 400/230 V, 1-phase, 50 Hz transformer is to be connected to a 25 Hz, the supply voltage should be 115 V.

**Description :** The locked rotor current in a 3-phase, star connected 15 , kW 4 , pole 230 V , 50 Hz induction motor at rated conditions is 50 A. Neglecting losses and magnetizing current, the approximate locked rotor line current drawn when the motor ... Hz supply is (A) 58.5 A (B) 45.0 A (C) 42.7 A (D) 55.6 A

**Last Answer :** The locked rotor current in a 3-phase, star connected 15 , kW 4 , pole 230 V , 50 Hz induction motor at rated conditions is 50 A. Neglecting losses and magnetizing current, the approximate locked rotor line current drawn when the motor is connected to a 236 , V 57 Hz supply is 45.0 A

**Description :** what will be the capacitance if three capacitors connected in parallel each having value of 0.5 micro Farad ?

**Last Answer :** the total capacitace when connected in parallel Tc=total capacitor c1=c2=c3=0.5uf Tc=c1+c2+c3 Tc=1.5uf

**Description :** A three phase induction motor is drawing 16 Ampere at 440 Volts. If the operating power factor of the motor is 0.90 and the motor efficiency is 92%, then the mechanical shaft power output of the motor is a) 12.04 kW b) 10.09 kW c) 10.97 kW d) None of the above

**Last Answer :** b) 10.09 kW

**Description :** Problem on temperature coefficient of resistance 1

**Last Answer :** Problem on temperature coefficient of resistance 1

**Description :** Problem on resistance and resistivity 1

**Last Answer :** Problem on resistance and resistivity 1

**Description :** Problem on temperature coefficient of resistance 3

**Last Answer :** Problem on temperature coefficient of resistance 3

**Description :** Problem on temperature coefficient of resistance 2

**Last Answer :** Problem on temperature coefficient of resistance 2

**Description :** Problem on resistance and resistivity 13

**Last Answer :** Problem on resistance and resistivity 13

**Description :** Problem on resistance and resistivity 12

**Last Answer :** Problem on resistance and resistivity 12

**Description :** Problem on resistance and resistivity 11

**Last Answer :** Problem on resistance and resistivity 11

**Description :** Problem on resistance and resistivity 10

**Last Answer :** Problem on resistance and resistivity 10

**Description :** Problem on resistance and resistivity 9

**Last Answer :** Problem on resistance and resistivity 9

**Description :** Problem on resistance and resistivity 8

**Last Answer :** Problem on resistance and resistivity 8

**Description :** Problem on resistance and resistivity 7

**Last Answer :** Problem on resistance and resistivity 7

**Description :** Problem on resistance and resistivity 6

**Last Answer :** Problem on resistance and resistivity 6

**Description :** Problem on resistance and resistivity 5

**Last Answer :** Problem on resistance and resistivity 5

**Description :** Problem on resistance and resistivity 4

**Last Answer :** Problem on resistance and resistivity 4

**Description :** Problem on resistance and resistivity 3

**Last Answer :** Problem on resistance and resistivity 3

**Description :** Problem on resistance and resistivity 2

**Last Answer :** Problem on resistance and resistivity 2

**Description :** A transformer at 25 Hz develops 20 W hysteresis loss and 50 W eddy current loss. If the applied voltage and frequency are doubled, the new core losses are (A) 140 W (B) 180 W (C) 240 W (D) 480 W

**Last Answer :** A transformer at 25 Hz develops 20 W hysteresis loss and 50 W eddy current loss. If the applied voltage and frequency are doubled, the new core losses are 240 W

**Description :** If an incandescent lamp of 80 ohms resistance takes a current of 0.75 ampere, what voltage is required to light it? A.45 volts B.60 volts c.23 volts D.None of these

**Last Answer :** V=IR = 80*0.75 = 60 volts

**Description :** A 3 phase, 400 volts, 50 Hz, 100 kW, 4 pole squirrel cage induction motor with a rated slip of 2% will have a rotor speed of: (A) 1500 rpm (B) 1470 rpm (C) 1530 rpm (D) 1570 rpm

**Last Answer :** 1470rpm

**Description :** If the source voltage for the voltage divider in question 50 supplies 150 volts, what is the total current through the voltage divider?

**Last Answer :** 495 mA.

**Description :** A 20 ohm resistor and a 60 ohm resistor are connected in parallel to a voltage source. If the current in the 60 ohm resistor is one ampere, the current in the 20 ohm resistor will be: w) 1/3 ampere x) 2/3 ampere y) 1 ampere z) 3 amperes

**Last Answer :** ANSWER: Z -- 3 AMPERES

**Description :** The reactance offered by a capacitor to an alternating current of frequency 50 Hz is 10 ohm. If frequency is increased to 100 Hz, the reactance will be (a) 2.5 ohm (b) 5.0 ohm (c) 20.0 ohm (d) 40.0 ohm

**Last Answer :** Xc = 1/(2*pi*f*c) so when f is double .... Xc will be half ... Ans is 5ohm

**Description :** The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_____ohms.

**Last Answer :** The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes 10 ohms.

**Description :** A single-phase, 230 V, 50 Hz ac mains fed step down transformer (4:1) is supplying power to a half-wave uncontrolled ac-dc converter used for charging a battery (12 V dc) with the series current limiting resistor being 19.04 Ohm. The charging current is (A) 2.43 A (B) 1.65 A (C) 1.22 A (D) 1.0 A

**Last Answer :** A single-phase, 230 V, 50 Hz ac mains fed step down transformer (4:1) is supplying power to a half-wave uncontrolled ac-dc converter used for charging a battery (12 V dc) with the series current limiting resistor being 19.04 Ohm. The charging current is 1.0 A

**Description :** lf slip of an induction machine is 0.02 and the stator supply frequency is 50 Hz, what will be the frequency of the rotor induced e.m.f.? (A) 10 Hz (B) 50 Hz (C) 1 Hz (D) 2500 Hz

**Last Answer :** 1hz

**Description :** An LED is operated on a 12 volt automobile circuit. The voltage drop across the LED is 2 volts and the current must be limited to 50 milliamps to prevent its overheating and destruction. What size resistor must be used? w) 60 ohms x) 100 ohms y) 120 ohms z) 200 ohms

**Last Answer :** ANSWER: Z -- 200 OHMS

**Description :** A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is (A) 4.5 V (B) 6.75 V (C) 9 V (D) 13.5 V

**Last Answer :** A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is 9 V

**Description :** In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is (A) sinusoidal current (B) constant dc current (C) continuous rectangular pulses (D) alternating rectangular pulses

**Last Answer :** In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is alternating rectangular pulses

**Description :** If 1 ampere current is flowing through a 100 mH coil, then energy stored in the coil is (a) 0.05 Joules (b) 0.5 Joules (c) 5.0 Joules (d) None of these

**Description :** Nodal analysis problem two current source

**Last Answer :** Nodal analysis problem two current source

**Description :** What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage: (A) Eddy Current and Hysteresis losses will be ... Current will be too much high (C) Transformer may start to smoke and burn (D) No effect

**Last Answer :** What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage: (A) Eddy Current and Hysteresis losses will be ... will be too much high (C) Transformer may start to smoke and burn (D) No effect

**Description :** The frequency of direct current is _______ (1) Zero (2) 50 HZ (3) 60 HZ (4) 100 HZ

**Last Answer :** Zero

**Description :** Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz. What will be the frequency of the rotor induced emf? (A) 10 Hz. (B) 50 Hz. (C) 1 Hz. (D) 2500 Hz.

**Last Answer :** Ans: C Given : s = 0.02 ; f = 50 Hz Therefore, frequency of rotor induced emf = s f = 0.02 x 50 = 1.0 Hz

**Description :** A circuit has a source voltage of 100 volts and two 50-ohm resistors connected in series. If the reference point for this circuit is placed between the two resistors, what would be the voltage at the reference point?

**Last Answer :** 50 volts.

**Description :** The line trap unit employed in carrier current relaying: (A) offers high impedance to 50 Hz power frequency signal (B) offers high impedance to carrier frequency signal (C) offers low impedance to carrier frequency signal (D) Both (A) & (C)

**Last Answer :** Ans: B The line trap unit employed in carrier current relaying offers high impedance to carrier frequency signal. Because carrier frequency range is 35 km – 500 kHz XL = 2Π f l Where f increases XL will also increases

**Description :** The frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full load speed is about (A) 50 Hz. (B) 20 Hz. (C) 2 Hz. (D) Zero.

**Last Answer :** (C) 2 Hz.

**Description :** For a 500 Hz frequency excitation, a 50 km long power line will be modeled as

**Last Answer :** For a 500 Hz frequency excitation, a 50 km long power line will be modeled as long line

**Description :** A 220/440 V, 50 Hz, 5 KVA, single phase transformer operates on 220V, 40Hz supply with secondary winding open circuited. Then (A) Both eddy current and hysteresis losses decreases. (B) Both ... same but hysteresis loss increases. (D) Eddy current loss increases but hysteresis loss remains the same.

**Last Answer :** (A) Both eddy current and hysteresis losses decreases.

**Description :** A tube has a transconductance of 800 mhos and a load resistor of 50 kohms. When control grid voltage varies by 6 volts, the plate voltage will vary by what amount?

**Last Answer :** 240 volts.

**Description :** The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The secondary output voltage will be (A) 3.6 V. (B) 2.5 V. (C) 3.0 V. (D) 6.0 V.

**Last Answer :** (C) 3.0 V.

**Description :** If the output of a half-wave rectifier is 50-volts peak, what is the average voltage

**Last Answer :** 15.9 volts.