Description : When a motor is just started, back emf is almost ______: a. Infinite b. zero c. minimum d. maximum
Last Answer : d. maximum
Description : Terminal potential difference of a battery is greater than its emf when a. the internal resistance of battery is infinite b. the internal resistance of battery is zero c. the battery is charged d. the battery is discharged
Last Answer : c. the battery is charged
Description : Resistance of an ideal insulator is a. Infinite b. Zero c. Finite d. depends upon nature
Last Answer : a. Infinite
Description : Conductivity of semi conductor is increased by: a) Decrease of temperature b) By keeping temperature constant c) Increase of temperature d) none of above
Last Answer : d) none of above
Description : Rest mass of the photon is a) Infinite b) Zero c) Very small d) 1.67 10-27 Kg
Last Answer : b) Zero
Description : The magnetic field is _________ inside a solenoid a) Zero b) uniform c) non-uniform d) infinite
Last Answer : b) uniform
Description : Why should a resistance be introduced in a circuit in series deliberately? a. to increase current b. to decrease current c. to control current d. just to give a good look to circuit
Last Answer : b. to decrease current
Description : Resistance of a wire on increasing its temperature will a. increase with rise in temperature b. decrease with rise in temperature c. will remain same d. depends upon altitude of experimentation
Last Answer : a. increase with rise in temperature
Description : With both ends of a three conductor cable disconnected and arranged without the conductors touching each other, an ohmmeter reading of 'zero' ohms between the ends of one conductor would indicate _____________. A. continuity B. a partial ground C. the resistance is infinite D. a short circuit
Last Answer : Answer: A
Description : Resistance of a super conductor is a. Finite b. Infinite c. Zero d. changes with every conductor
Last Answer : c. Zero
Description : A conductor of length L has current I passing through it, when it is placed parallel to a magnetic field. The force experienced by the conductor will be (a) zero (b) BLI (c) B2LI (d) BLI2
Last Answer : (a) zero
Description : If velocity of a conductor moving through a magnetic field ‘B’ is made zero, then Motional emf will be: a. –VBL b. –V/BL c. – BL/V d. zero
Last Answer : a. –VBL
Description : Internal resistance is the resistance offered by a. source of e m f b. Conductor c. Resistor d. Capacitor
Last Answer : a. source of e m f
Description : The resistance of a few meters of wire conductor in closed electrical circuit is?
Last Answer : The resistance of a few meters of wire conductor in closed electrical circuit is practically zero.
Description : If a material object moves with the speed of light ‘c’ its mass becomes a) equal to its rest mass b) Four times of its rest mass c) Double of its rest mass d) Infinite
Last Answer : d) Infinite
Description : With increase in the velocity of an object its mass will a) Increase b) Decrease c) Remain constant d) None of the above
Last Answer : a) Increase
Description : If PN junction is forward biased its resistance is (a) Zero (b) Infinity (c) A few ohm (d) A few kilo ohms
Last Answer : c) A few ohm
Description : A wire of uniform area of cross-section A length L and resistance R is cut into two parts. Resistivity of each part a. remains the same b. is doubled c. is halved d. becomes zero
Last Answer : a. remains the same
Description : Pick out the correct statement. (A) Like internal energy and enthalpy, the absolute value of standard entropy for elementary substances is zero (B) Melting of ice involves increase in enthalpy and ... of an ideal gas depends only on its pressure (D) Maximum work is done under reversible conditions
Last Answer : (D) Maximum work is done under reversible conditions
Description : The unit of absolute permittivity of a medium is
Last Answer : Farad/ metre
Description : Tick the wrong statement. a) Velocity of light is independent of the motion of the observer. b) Velocity of light in free space is the same in all directions. c) Velocity of light in free space is different in different directions. d) Absolute motion or absolute rest is meaningless to talk about
Last Answer : c) Velocity of light in free space is different in different directions
Description : The potential difference set up across the depletion region is called (a) Absolute potential (b) neutral potential (c) reverse potential (d) potential barrier
Last Answer : (d) potential barrier
Description : The temperature at which material show super conductivity is a) Super temperature b) Critical temperature c)Kelvin temperature d)Absolute
Last Answer : d)Absolute
Description : If your multimeter gives a reading in ohms when testing each end of each conductor of a three-conductor cable, this indicates ______________. A. continuity of the conductor B. an infinite resistance C. the presence of a partial ground D. that the conductor is not short circuited
Description : If you disconnect and arrange both ends of a three conductor cable, without any contact between the individual conductors, an indicated ohmic value between the ends of a single conductor would indicate ... resistance C. the presence of a partial ground D. that the conductor is not short circuited
Description : The force between two long parallel conductors is inversely proportional to (a) radius of conductors (b) current in one conductor (c) product of current in two conductors (d) distance between the conductors
Last Answer : (d) distance between the conductors
Description : The left hand rule correlates to (a) current, induced e.m.f. and direction of force on a conductor (b) magnetic field, electric field and direction of force on a conductor (c) self induction, ... and direction of force on a conductor (d) current, magnetic field and direction of force on a conductor
Last Answer : (d) current, magnetic field and direction of force on a conductor
Description : Fleming's left hand rule is used to find (a) direction of magnetic field due to current carrying conductor (b) direction of flux in a solenoid (c) direction of force on a current carrying conductor in a magnetic field (d) polarity of a magnetic pole
Last Answer : (c) direction of force on a current carrying conductor in a magnetic field
Description : The two conductors of a transmission line carry equal current I in opposite directions. The force on each conductor is (a) proportional to 7 (b) proportional to X (c) proportional to distance between the conductors (d) inversely proportional to I
Last Answer : (b) proportional to X
Description : A permeable substance is one (a) which is a good conductor (6) which is a bad conductor (c) which is a strong magnet (d) through which the magnetic lines of force can pass very easily
Last Answer : (d) through which the magnetic lines of force can pass very easily
Description : What is a semi conductor?
Last Answer : Substance as germanium or silicon whose electrical conductivity is intermediate between that of a metal and an insulator; its conductivity increases with temperature and in the presence of impurities
Description : Forward current through a semi-conductor diode circuit is due to ________ (a) Minority carriers (b) majority carriers (c) holes (d) electrons
Last Answer : (b) majority carriers
Description : First super conductor was discovered by a) Kelvin b) Hertz c)Einstein d) Kamerlingh Ornes
Last Answer : d) Kamerlingh Ornes
Description : A doped semiconductor is called : a) Extrinsic b) Intrinsic c) Insulator d) Conductor
Last Answer : b) Intrinsic
Description : Due to self-inductance, the coil wires are known as: a. Insulator b. Conductor c. Inductor d. Semi-conductor
Last Answer : c. Inductor
Description : A current of 5.8 A flows through a 0.25 m long straight conductor which is kept perpendicular in a region of uniform magnetic field of 3.7 T . The force on conductor is a) 5.4 N b) 2.4 N c) 3.4 N d) 6.4 N
Last Answer : a) 5.4 N
Description : ___________ is not affected by a magnetic field a) Change in magnetic flux b) a moving electron c) a stationary proton d) current flowing in a conductor
Last Answer : c) a stationary proton
Description : If 1 ampere current flows through 2m long conductor the charge flow through it in 1 hour will be a. 3600C b. 7200C c. 1C d. 2C
Last Answer : a. 3600C
Description : A wire having very high value of conductance is said to be a. very good conductor b. moderately good conductor c. an insulator d. None
Last Answer : a. very good conductor
Description : Explain the suitability of aluminium as an electrical conductor with respect to its mechanical and electrical properties.
Last Answer : Following are requirements of conductor:- i) High conductivity : Material should have high conductivity, So that * cross section of conductor (size) reduces, * Copper losses reduces, * So Efficiency ... . Boiling point is 1820°C 9. Specific gravity is 2.7 10. High resistance to corrosion.
Description : Change in volume of metals from absolute zero temperature to their melting points is (A) Almost same for all metals (B) Different for different metals (C) Less for low melting point metals (D) Less for high melting point metals
Last Answer : (A) Almost same for all metals
Description : The pole faces of U-shaped magnet in a moving coil galvanometer are made concave to a) decrease the strength of magnetic field b) create a non-uniform magnetic field c) make the magnetic field radial d) All of these
Last Answer : c) make the magnetic field radial
Description : An open coil in a transformer will be indicated by which of the listed conditions? A. 'zero' resistance accompanied by high inductance B. no resistance accompanied by stray inductance C. infinite resistance in addition to no inductance D. infinite resistance in addition to normal inductance
Last Answer : Answer: C
Description : A material with zero resistivity is said to have a) Zero conductance b) Infinite conductance c) Zero resistance d) Infinite resistance
Last Answer : c) Zero resistance
Description : A infinite resistance is considered as a/an a) Closed path(short circuit) b) Open path c) Not defined d) Ammeter with zero reading
Last Answer : b) Open path
Description : If Laplace equation satisfies, then which of the following statements will be true? a) Potential will be zero b) Current will be infinite c) Resistance will be infinite d) Voltage will be same
Last Answer : b) Current will be infinite
Description : Why the input resistance of an ideal OPAMP is infinite and output resistance is zero? secondly, how can we measure these resistances(input and output) in case of an ideal OPAMPand Real OP-AMP in the following conditions when 1- load is not connected. 2- load is connected.
Last Answer : Ans- Ideal OP-AMP is a power ful concept. If one goes through the history of amplifying devices it becomes clear that less it loads the previous stage better the output signal. ie ... . Can refer application notes by device manufacturer available in internet for more precise and practical solutions.
Description : 57 In a transformer the resistance between its primary and secondary is A. Zero B. 1Ω C. 1000 Ω D. Infinite
Last Answer : D. Infinite
Description : A capacitor is to be tested with a megohmmeter. If the meter is connected to a shorted capacitor, the meter pointer should _____________. A. immediately swing to the maximum resistance value ... and gradually decrease D. swing to zero then gradually increase with slight pointer movements down scale
Last Answer : Answer: B
Description : Air gap has_______eluctance as compared to iron or steel path (a) little (b) lower (c) higher (d) zero
Last Answer : (b) lower