Description : When a motor is just started, back emf is almost ______: a. Infinite b. zero c. minimum d. maximum
Last Answer : d. maximum
Description : In the plane of AC generator coil is parallel to the field, then emf induced in coil is: a. maximum b. minimum c. zero d. intermediate
Last Answer : b. minimum
Description : In the plane of the A.C generator coil is perpendicular to the field, then induced emf in the coil is: a. Maximum b. minimum c. zero d. intermediate value
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 : In an oil-lubricated journal bearing, coefficient of friction between the journal and the bearing. [IES-1995] (a) Remains constant at all speeds. (b) is minimum at zero speed and increases ... speed. (d) becomes minimum at an optimum speed and then increases with further increase in speed.
Last Answer : (d) becomes minimum at an optimum speed and then increases with further increase in speed.
Description : A wire loop is moved parallel to a uniform magnetic field. The induced emf in the loop: a. depends on the shape b. depends on area c. depends on nature of loop d. zero
Last Answer : d. zero
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 : The induced emf is produced in a circuit due to: a. Initial magnetic flux b. final magnetic flux c. Change of magnetic flux d. constant magnetic flux
Last Answer : d. constant magnetic flux
Description : When two gases are mixed, the entroру (a) Remains constant (b) Decreases (c) Increases (d) Becomes zero
Last Answer : Ans:(c)
Description : When water freezes its density – (1) Decreases (2) Becomes Zero (3) Remains constant (4) Increases
Last Answer : (1) Decreases Explanation: Water at ordinary temperatures contracts and in-creases in density as it is cooled, like most substances. But at about 4°C it reaches a maximum density and then decreases in density as it approaches the freezing point. This is referred to as anomalous property of water.
Description : By increasing the current, the drift velocity A. decreases B. increases C. remains constant D. becomes zero
Last Answer : remains constant
Description : As the ball falls towards the ground, its velocity A. increases B. decreases C. remains constant D. becomes zero
Last Answer : increases
Description : When water freezes its density (1) Decreases (2) Becomes Zero (3) Remains constant (4) Increases
Last Answer : Decreases
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 : With increase in temperature, the thermal conductivity of most liquids (A) Increases (B) Decreases (C) Remain same (D) First increases upto a certain temperature and then becomes constant
Last Answer : (C) Remain same
Description : On increasing the reverse bias to a large value in a p-n junction diode current (a) Increases slowly (b) Remains fixed (c) Suddenly increases (d) Decreases slowly
Last Answer : (c) Suddenly increases
Description : In forward bias, the width of potential barrier __________ (a) Increases (b) decreases (c) remains same (d) no effect
Last Answer : (b) decreases
Description : The direction of induced EMF can be found with the help of -
Last Answer : Lenz’s Law
Description : The induced emf in a coil depends upon: a. Strength of magnetic field b. Resistance of the coil c. area of the coil d. All of them
Last Answer : d. All of them
Description : Which of the following will produce an induced emf: a. Changing area of coil b. Changing magnetic flux c. changing orientation of coil d. all of them
Last Answer : c. changing orientation of coil
Description : The phenomena of induced emf was observed by Faraday and Henry in: a. 1931 b. 1831 c. 1535 d. 1940
Last Answer : a. 1931
Description : The phenomenon of producing emf in the coil due to change of current in the coil itself is called: a. mutual induction b. self-induction c. self-inductance d. mutual inductance
Last Answer : d. mutual inductance
Description : The current flowing in a coil due to induced emf depends upon: a. shape of coil b. resistance of coil c. area of coil d. magnetic flux
Last Answer : a. shape of coil
Description : A neon flashlight cell with an emf of 1.5V gives a current of 15A when connected directly to an ammeter of resistance 0.04?. Internal resistance of the cell is a. 0.0004? b. 0.06? c. 0.10? d. 0.13?
Last Answer : b. 0.06?
Description : With the increase of pressure, the boiling point of any substance - (1) Increases (2) Decreases (3) Remains Same (4) Becomes zero
Last Answer : (1) Increases Explanation: The temperature stays the same until all the liquid has vaporized. As the temperature of a liquid rises, the pressure of escaping vapor also rises, and at the boiling point ... vapor is equal to that exerted on the liquid by the surrounding air, causing bubbles to form.
Description : With the increase of pressure, the boiling point of any substance – (1) Increases (2) Decreases (3) Remains Same (4) Becomes zero
Description : The surface tension of water on adding detergent to it – (1) increases (2) decreases (3) no change (4) becomes zero
Last Answer : (2) decreases Explanation: In the solid and liquid phase, water molecules are bonded to each other by virtue of an interaction between hydrogen atoms on one molecule and the oxygen atom of another - the process ... to as "hydrogen bonding." The result is a kind of "skin" on liquid water's surface.
Description : .If we narrow the distance between two slits in Young’s experiment the fringes width __________. A. Increases B. Decreases C. Remains same D. becomes zero
Last Answer : B. Decreases
Description : The surface tension of water on adding detergent to it (1) increases (2) decreases (3) no change (4) becomes zero
Last Answer : decreases
Description : If magnetic field is doubled then magnetic energy density becomes: a. Four times b. Two times c. Three times d. Six times
Last Answer : c. Three times
Description : A solenoid has n turns and length l. If length is reduced to l/2 and turns are doubled then magnetic field B produced by it becomes equal to a) 2B b) 4B c) 1/2 B d) None of these
Last Answer : a) 2B
Description : A proton moves in a uniform magnetic field in a circular path of radius R. If the energy of proton is doubled then the new radius becomes a) R √2 b) 2R c) R 2 d) √2 R
Last Answer : d) √2 R
Description : Thevelocityfactor of a transmissionline a. depends on the dielectric constant of the material used b. increases the velocity along the transmission line c. is govern by the skin effect d. is higher for a solid dielectric than for air
Last Answer : a. depends on the dielectric constant of the material used
Description : Two electron beams move parallel to each other. The nature of force between them is a) Attractive b) Repulsive c) Dependent on magnitude of velocity d) None
Last Answer : b) Repulsive
Description : When a detergent is added to pure water, its surface tension – (1) increases (2) decreases (3) remains constant (4) becomes infinite
Last Answer : (2) decreases Explanation: When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding ... of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.
Description : When a catalyst increases the rate of forward reaction, the value of rate constant (A) Increases (B) Decreases (C) Remain same (D) Becomes infinite
Last Answer : (A) Increases
Description : When a detergent is added to pure water, its surface tension (1) increases (2) decreases (3) remains constant (4) becomes infinite
Description : The termcritical angle describes a. the point at which light is refracted b. the point at which light becomes invisible c. the point at which light has gone from the refractive mode to the reflective mode d. the point at which light has crossed the boundary layers from one index to another
Last Answer : c. the point at which light has gone from the refractive mode to the reflective mode
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 : When a uniform magnetic field B is applied to a current carrying coil, the coil will rotate in such a manner that its plane a) becomes parallel to B b) becomes anti-parallel to B c) makes an angle of 600 with B d) becomes perpendicular to B
Last Answer : d) becomes perpendicular to B
Description : If the distance between the two charge bodies is halved, the force between them becomes: (a) Half (b) Four time (c) One fourth (d) Doubled
Last Answer : (c) One fourth
Description : Pick out the wrong statement. (A) When the concentration difference for the mass transfer becomes zero at the bottom of the gas absorption tower, then the upper end of the operating line touches the ... fixed gas flow rate, the slope of the operating line decreases, in case of gas absorption process
Last Answer : (C) The operating line lies above the equilibrium curve in case of a gas desorber
Description : An ideal gas is compressed in a cylinder so well insulated that there is essentially no heat transfer. The temperature of gas a. Remains constant b. increases c. decreases d. is basically zero
Description : With increase in the shear rate, the apparent viscosity of pseudo-plastic fluids (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease; depends on the magnitude of shear rate
Last Answer : (B) Decreases
Description : The counter EMF produced in the windings of a DC motor is 'zero' when the ____________. A. armature has just begun to turn B. armature is not turning C. motor is almost up to rated speed D. motor is at rated speed
Last Answer : Answer: B
Description : How the magnitude of rotor emf is related to the slip in an I M?
Last Answer : Rotor circuit emf per phase E2’=SE2
Description : What is the effect on the magnitude of emf generated in an AC generator if the speed of rotation is increased?
Last Answer : The magnitude of emf generated increases.
Description : 6 In a two winding transformer, the primary and secondary induced emf E1 & E2 are always A. equal in magnitude B. anti phase with each other C. in phase with each other D. determined by load on transformer secondary
Last Answer : C. In phase with each other
Description : The resistivity of ..... decreases with the increase in temp. a. gold b. silver c. copper d. silicon
Last Answer : d. silicon
Description : When a man circles round the earth in a satellite, then (a) His mass becomes zero but weight remains constant (b) Mass remains constant but weight becomes zero (c) Both mass and weight remain constant (d) Both mass and weight remain zero
Last Answer : Ans:(b)