Question

plz any one these are some mcqs i am preparing for a test i m not sure with the answers of these mcqs this is not a homework not an online course exam so feel free to answer these thankx

MCQS
01. Changes of equal magnitude are separated by some distance. If the changes are in creased by 10% to get the same force between them their separation must be.
(a) Increase by 21% (b) Increase by 10%
(c) Decreased by 10% (d) None of the above is correct
02. If the distance between two electric charges is doubled, the force experienced between them will be.
(a) One-fourth (b) Half
(c) Double (d) four-time
03. The phenomenon of an uncharged body getting charged merely by nearness of a charged body is called the.
(a) Induction (b) Attraction
(c) Magnetic effect, (d) Chemical effect.
04. When an uncharged body is placed near a charged body.
(a) Then uncharged body is attracted first and then charged by induction.
(b) Get charged by induction and then attracted towards the charging body.
(c) Gets charged by conduction.
(d) Remains as such
05. The space surrounding a charge within which the influence of its charge extends is known as.
(a) Electric field (b) Magnetic field
(c) Line of force (d) Electric intensity
06. A region around a stationary electric charge has.
(a) Electric field (b) Magnetic field
(c) Both electric and magnetic fields. (d) Neither electric nor magnetic field.
07. The number of tubs of force passing through a surface in an electric filed is known as.
(a) Electric charge density (b) Electric flux density
(c) Electric flux (d) Magnetic flux
08. Electric flux emanating from an electric charge of + Q coulombs is.
(a) +Q (b) Q%
(c) –Q (d) 1/Q
09. For any medium, electric flux density D and electric intensity E are related as D=
(a) Eo £ (b) £7eo
(c) EoGrE (d) E/eoer
10. Electric intensity at a surface of a conduction body having a charge density of _ coulombs per unit of surface area is
(a) σ/2 r
(b) (b) σ 2 r
(c) σ r
(d) σ 2
11. Electric potential at a point situated at a distance ‘d’ from a point charge varies as.
(a) D2 (b) 1/d
(c) 1/d2 (d) d
12. The potential inside a charged hollow sphere is.
(a) Zero (b) Same as that on the surface.
(c) Less than that on the surface (d) None of the above
13. Voltage applied across a glass dielectric produces an electric field 10 time of that of air. The dielectric constant for glass is.
(a) 0.1 (b) 10
(c) 100 (d) 0.01
14. The relation between electric intensity E voltage applied V and distance d between the plates of a parallel plate condenser is.
(a) £=£ (b) E=Vxcl.
(c) E=Zr- (d) £=Fxc/²
15. A capacitor consists of two.
(a) Conductors separated by an insulator called the dielectric.
(b) Insulators separated by a conductor.
(c) Insulators separated by a dielectric.
(d) Conductors separated by air medium only
16. In a capacitor, the electric charge is stored
(a) Metal plates. (b) Dielectric
(c) Both (a) & (b) (d) None of these.
17. If the dielectric of a capacitor is replaced by a conducting material the.
(a) Capacitor will get heated up owing to eddy currents.
(b) Plats will get short-circuited
(c) Capacitor can store infinite charge
(d) Capacitor will become very high
18. The total excess or deficiency of electrons in a body is called the.
(a) Current (b) Voltage
(c) Charge (d) Potential gradient
19. The charge on an isolated conductor resides.
(a) At the conductor surface. (b) Inside the conductor
(c) Partly at the surface and party inside the conductor.
(e) None of the above
20. The capacitance of a parallel plate capacitor is not affected by
(a) Are of plates (b) Thickness of plates.
(c) Separation between plates (d) Nature of dielectric.
21. Capacitance of a parallel plate capacitor in creases with.
(a) Increase in plate area and decrease in separation between plates.
(b) Increase in plate area and in separation between plates.
(c) Decrease in plate area and in separation between the plates.
(d) Decrease in plate area and increase in applied voltage.
22. A parallel plate capacitor has capacitance of 10 uF. If the linear dimensions of the plates are doubled and the separation between them is also doubled the value of the capacitor would be.
(a) 10 u F. (b) 20 u F
(c) 5 u F (d) 40 u F
23. The property of a material which opposes the production of magnetic flux in it is known.
(a) Mmf (b) Reluctance
(c) Permeance (d) Permittivity
24. The capacitance of a cylindrical capacitor is given as length, keeping the volume constant. The new resistance will be
(a) R/9 (b) R/3
(c) 9R (d) 3R
25. The wire is stretched to its double the length. The new resistance will be.
(a) 4-time the original resistance. (b) Double the original resistance
(c) Half the original resistance (d) One-fourth of the original resistance.
26. A length of wire having a resistance of 1 ft is cut into four equal parts and these four part are bundled together side by side to form a wire the new resistance will be.
(a) ¼ Q (b) 1/16 a.
(c) 4 a (d) 16 a
27. The resistance between the opposite faces of lm cube is found to be lft. If its length is increased to 2m, with its volume remaining the same then its resistance between the opposite face along its length is.
(a) 2 ft. (b) 4 ft
(c) 1 ft (d) 8 ft
28.A wire of length / and of circular cross-section of radius r has a resistance of R ohms. Another wire of same material and of x-sectional radius 2 r will have the same R if the length is.
(a) 2 l (b) l l l
(c) 4 l (d) l 2
29. If the diameter of the wire is halved its current carrying capacity will become about.
(a) One-fourth (b) Half
(c) Twice (d) Four-time
30. Specific resistance of a conductor depends upon.
(a) Dimensions of the conductor.
(b) Composition of conductor material
(c) Resistance of the conductor
(d) Resistance of the conductor
31. Temperature coefficient of resistance is defined as.
(a) Increase in resistance per ohm per 0 C
(b) Increase in resistance per o C
(c) Decrease in resistance per o C
(d) The ratio of decrease in resistance per o C
32. The resistance of a field coil is 55 Q at 25o C and 65 Q at 75o C. The temperature coefficient of resistance of field coil at 0o C is a/a o C-1.
(a) 0.2 (b) 0.004
(c) 0.0004 (d) 0.00364
33. When an electric current flows through a conductor, its temperature rises. This is because of.
(a) Mutual collisions between metal atoms.
(b) Mutual collisions between conducting electrons.
(c) Collisions between conduction electrons and atoms.
(d) Release of conduction electrons from parent atoms
34.Energy expended or heat generated in joules when a current of l amperes flows through a conductor of resistance R ohms for t seconds is give as.
(a) l R 2 T (b) l 2 RT
(c) l RT (d) None of these
35. Which of the following do not use heating effect of electric current?
(a) Electric furnace (b) Geyser
(c) Electric oven (d) Immersion heater
36. Temperature coefficient of resistance is defined as
(a) Increases in resistance per ohm per 0 C.
(b) Increase in resistance per 0 C
(c) Decrease in resistance per ohm per 0 C.
(d) The ratio of decrease in resistance per 0 C to the resistance at 0 C.
37. The resistance of a field coil is 55 Q at 250 C. and 65 Q at 750 C. The temperature coefficient of resistance of field coil at 00 C is a/a0 C.
(a) 0.2 (b) 0.004
(c) 0.0004 (d) 0.0036
38. When an electric current flows through a conductor, its temperature rises. This is be cause of
(a) Mutual collisions between metal atoms.
(b) Mutual collisions between conduction electrons
(c) Collisions between conduction electrons and atoms.
(d) Release of conduction electrons from parent atoms.
39. Four resistors, each of resistance R ohms are available. The minimum resistance of the combination will be
(a) 4 R (b) R
(c) R % (d) Rl 5
40. A resistance of 30 Q is connected across 240 V supply. If a resistance of R ohms is connected in parallel with a 30 Q resistor across the same supply, the current draw becomes triple of original one. The value of unknown resistance R is.
(a) I 5 a (b) l 0Q
(c) 5 a (d) 30 ft.
41. Twelve identical wires of resistance 6ft each are arranged to form the edges of a cube. The effective resistance between the opposite corners of the cube is.
(a) 6ft (b) 5ft
(c) 8ft (d) 4.5ft
42. How are 500ft resistors connected so as to give an effective resistance of 750 ft?
(a) Three resistors of 500ft each, in parallel.
(b) Three resistors of 500ft each, in series.
(c) Two resistors of 500ft each, in parallel.
(d) Two resistors of 500ft each, in parallel and the combination in series with another 500ft resistor.
43. A current of 24 A divides between three branches in parallel of resistances 4ft, 6ft & 12 ft respectively. The currents in various branches are.
(a) 12A, 8A & 4A (b) 96/22A, 144/22A & ^A.
(c) 4A, 8A & 12 A (d) 6A, 8A, 10A
44. A keeper is used for
(a) Restoring of lost flux. (b) Amplification of flux
(c) Providing a closed path for the magnetic flux
(d) Changing the direction of magnetic lines of force.
45. Poles of a magnet
(a) Cannot be separated (b) Can be separated
(c) Can be used separately.
(e) Can be separated by breaking it into pieces.
46. The direction of magnetic lines of force is.
(a) From South Pole to North Pole.
(b) From North Pole to South Pole.
(c) From one end of magnet to another
(d) None of the above.
47. The no of line of force in magnetic material are called the
(a) Line of forces (b) Electric flux
(c) Tube of induction (d) susceptibility
48. The number of lines of force per unit area is a measure of.
(a) Magnetic flux density (b) magnetic field intensity
(c) mmf (d) susceptibility
49. The unit of magnetic flux density in SI system is
(a) AT/m (b) Weber
(c) Tesla (d) Coulombs/m 2
50. The relation between magnetizing force (H), magnetic flux density (B) and permeability of material u is given as.
(a) B=M-H (b) B= ų H
(c) B=m0H/m (d) B= ų /H.ų
51.The direction of magnetic field around a current carrying conductor can be determined by.
(a) Cork screw rule (b) right hand rule,
(c) End rule (d) Thumb rule
52. The polarity of the pole can be determined by.
(a) End rule (b) Cork screw rule
(c) Thumb rule (d) Left hand rule
53. The direction of magnetic flux in a current carrying conductor shown in figure below.
(a) Up wards (b) Down wards
(c) Clock wise (d) Counter clockwise
54. If the two conductors carry current in opposite directions there will be.
(a) Force of attraction between the two conductors.
(b) A force of repulsion between the two conductors.
(c) No force between them (d) none of the above
55. A straight conductor of circular x-section carries a current. Which one of the following statements is true in this regard?
(a) No force acts on the conductor at any point.
(b) An axial force acts on the conductor tending to increase its length.
(c) A radial force acts towards the axis tending to reduce its cross-section.
(d) A radial force acts away from the axis tending to increase its cross-section.
56. Two infinitely long parallel wires are carrying equal currents in the same direction the current in each conductor is doubled, keeping the separation between wires unchanged, the force experienced between them will become.
(a) One-fourth (b) One-half
(c) Twice (d) four times
57. A ring shaped with fixed number of turns on it carries a current of certain magnitude, if an iron core is threaded into the coil with out any change in coil dimensions the magnetic induction density will.
(a) Increase (b) reduce
(c) Remain unaffected (d) Unpredictable
58. The ratio of total flux (flux in the iron path) to useful flux (flux in the air gap) is known as factor.
(a) Utilization (b) Fringing
(c) Leakage (d) Depreciation
59. When a magnetizing force is removed from a material, the kind of magnetism that remains is called the ---------- magnetism.
(a) Residual (b) Induced
(c) Stray (d) None of the above
60. The relative permeability of ferromagnetic materials is about.
(a) Unity (b) 10
(c) 100 (d) 1000
61. The materials having low retentivity are suit able for making magnets.
(a) Permanent (b) Temporary
(c) Weak (d) Strong
62. The magnetism present in a piece of soft steel held near a magnet is called the
(a) Residual (b) Insulated
(c) Stray (d) None of these
63. Materials subjected to rapid reversals of magnetism should have.
(a) High permeability and low hysteresis loss.
(b) Large B-H loop area.
(c) Large coercivity and high retentivity
(d) Low permeability and large coercivity
64. When a single turn coil rotates in a uniform magnetic field, at a uniform speed the induced emf will be.
(a) Alternating (b) Steady
(c) Pulsating (d) None of these.
65. The principal of dynamically induces emf is utilized in a.
(a) Choke (b) Transformer
(c) Generator (d) Thermo-couple.
66. A minus (-) sign is required to be placed before the right hand side of the expression for emf induced just to indicate the phenomenon explained by
(a) Lenz (b) Faraday
(c) Coulomb (d) Fleming’s
67. The direction of dynamically induced emf in a conductor can be determined by.
(a) Fleming’s left hand rule (b) Fleming’s right hand rule
(c) Helix rule (d) Corkscrew rule.
68. The Fleming’s right hand rule correlates.
(a) Current, induced emf and magnetic field
(b) Magnetic field, electric field, induced emf.
(c) Direction of magnetic field.
(d) Direction of flow of current and direction of force experienced
(e) Direction of field motion of conductor and direction of induced emf.
69. In Fleming’s right hand rule thumb always represents direction of.
(a) Motion of conductor. (b) Field
(c) Induced voltage (d) None of the above
70. The principal of statically induced emf is utilized in.
(a) Transformer (b) Monitor
(c) Generator (d) Battery
71. A small capacitance is added to a highly inductive circuit.
(a) The angle between voltage and current will increase
(b) The pf will decrease
(c) The power drawn will decreases
(d) The pf will increase
72. In an R-l-C current power is consumed
(a) In resistance only and is equal to l-R
(b) Exchange of power does not take place between resistance and supply mains.
(c) Exchange of power takes place between capacitor and supply mains.
(d) All of the above
73.The symbol j represents rotation of a phasor through degrees.
(a) Clock wise, 900
(b) Clockwise 1800
(c) Counter- clockwise 900
(d) Counter-clockwise 1800
74. The operating j has a numerical value of
(a) 0 (b) √-1
(c) -1 (d) +1
75. The numerical value of operator j 2 is equal to.
(a) +1 (b) –1
(c) Zero (d) √-1
76. The phasor C can be represented in symbol or rectangular form as
(a) a + b (b) ab
(c) √ a 2 + b2 (d) a+ jb
77. The conjugate of (-a-jb) is.
(a) (ra + jb) (b) (a + jb)
(c) (a-jb) (d) (-jb-a)
78. While drawing a phasor diagram for a parallel circuit is taken as reference phasor.
(a) Current (b) Voltage
(c) Power (d) None of these
79.For connecting two voltage sources in parallel, which of the parameters should be equal?
(a) Phase and magnitude. (b) Frequency and magnitude
(d) Phase and frequency
(d) Frequency, phase and magnitude.
80. Capacitive susceptance is expressed in
(a) Ohms (b) farads.
(c) Seimens (d) None of the above
81. Capacitive susceptance is a measure 0%
(a) A purely capacitive circuit’s ability to pass current
(b) A purely capacitive circuit’s ability to resist the flow of current.
(c) The extent of neutralization of reactive power in a circuit.
(d) Reactive power in a circuit.

82. Power factor of an inductive circuit is usually improved by adding a capacitor to it in.
(a) Series (b) Parallel
(d) Either in series or in parallel
83. Admittance of a coil having a resistance of 6Q and inductive reactance of 8 £ 2 is expressed in complex from as.
(a) (0.06-j 0.08) (b) (0.06+j 0.08)
(c) (0.08- j 0.06) (d) (0.08 + 0.06)
84. In transient circuit analysis the particular solution given response.
(a) Transient (b) Steady state
(c) Neither (d) Both
85. Inductance affects the flow of direct current at the time of
(a) Turning off (b) Turning on
(c) Turning on and off (d) None of the above
86. Time constant of an inductive circuit increase with the increase in.
(a) Inductance (b) Resistance
(c) Voltage (d) None of the above
87.The time constant for an R-1 circuit is defined as the time taken by the current to be come of its final value.
(a) 36.8% (b) 63.2%
(c) 50% (d) 100%
88. The current through an inductor follows.
(a) A linear growth (b) A linear decay
(c) An exponential growth (d) an exponential decay.
89. A series RL circuit with R=100 ohm; L=50H, is supplied to a dc source of 100 V. The time taken for the current to rise 70% of its steady state value is.
(a) 0.3 s (b) 0.6 s
(c) 2.4 s
(e) 70% of time required to reach steady state
90. A coil with a certain number of turns has a specified time constant. If the number of turns is doubled, its time constant would.
(a) Remain unaffected (b) Become Doubled
(c) Become four fold (d) Get halved
91. At a certain current, the energy stored in an iron- cored coil is 1000 j and its copper loss is 2000 w .The time constant (in second) of the coil is.
(a) 0.25 (b) 0.5
(c) 1.0 (d) 2.0
92. In an R-C series circuit excited by a dc voltage of V volts, the initial current is.
(a) 0 V (b) 1 V
(c) 2 V (d) ∞
93. Potential difference across a capacitor of capacitance 20 up is increase uniformly from 0 to 240 V in 1 second. The charging current will be.
(a) 4/C (b) C/4
(c) 2C (d) 4C
94. Electric pressure is also called the
(a) Resistance (b) Voltage
(c) Power (d) Energy
95. Electric pressure is also called the.
(a) Resistance (b) Voltage
(c) Power (d) energy
96. Resistance of human body is about
(a) 10 Q (b) 100 Q
(c) 1000 Q (d) 10000 Q
97. The ratio of voltage and electric current in a closed circuit.
(a) Remains constant (b) Varies
(c) Increases (d) Falls
98. The relation between voltage, current and resistance for closed circuit is given as.
(a) 1=V*R (b) I=V/R
(c) R=I/V (d) V=I/R
99. If in a circuit the voltage is reduced to half and resistance is double, the current will be come.
(a) Four time (b) Double
(c) A Quarter (d) Half
100.The condition for the validity under ohm’s law is that the.
(a) Temperature should remain constant
(b) Current should be proportional to volt age
(c) Resistance must be wire wound type.
(d) All of the above
101. Filament lamp makes use of
(a) Chemical effect (b) Heating effect
(c) Magnetic effect (d) none of the above
102. Resistance of a 200 W, 250 V lamp will be.
(a) 625 Q (b) 1250 Q
(c) 312.5 Q (d) 31.25 Q
103. The cold resistance of a 100 W, 250 V tungsten lamp will be while cold resistance of tungsten filament lamp is about one- tenth of the hot resistance.
(a) 62.5 Q (b) 625 Q
(c) 6,250 Q (d) none of the above
104. For the same voltage, the ratio of resistances of 25 W and 100 W lamps will be.
(a) 1:1 (b) 2:1
(c) 4:1 (d) 1:4
105. The condition for the validity under Ohm’s law is that the.
(a) Current should be proportional to voltage
(b) Resistance must be wire wound type.
(c) All of the above
106. The curve representing Ohm’s law is
(a) Sine function (b) Linear
(c) A parabola (d) A hyperbola.
107. Which of the following statements is correct regarding resistance?
(a) The resistance of a conductor is the hindrance by which the conductor opposes the flow of current through it.
(b) The resistance of wire is independent of the temperature for most of the materials.
(c) The resistance of a wire does not depend upon its material
(d) None of the above
108. The transient current in loss free L-C circuit, when excited from an ac source sine wave.
(a) An under damped (b) An undamped
(c) An over damped (d) Critically damped
109.In a loss free R-L-c circuit the transient current will be.
(a) Square wave (b) Oscillating
(c) Sinusoidal (d) Non-oscillating
110. In an R-L circuit connected to an alternating sinusoidal voltage, the magnitude of transient current primarily depends on the.
(a) Instant in the voltage cycle at which circuit is closed.
(b) Impedance of the circuit
(c) Frequency of the voltage
(d) Peak value of steady state current.
111. In the circuit given below, the initial current 1(0)=25A. the current response is given.
(a) 12.5<r3, A. (b) 25<<r3t, A
(c) 25e3,A (d) 25er’/ 3,A
112. An R-L circuit is fed from an ac source of voltage V max sin (W/+a) the transient component of the current, when the circuit is switched on, will be zero if.
(a) A=0 (b) A=900
(b) Tan -(wl/r) (d) A=1350
113. The electrons revolve around the nucleus with high velocity. The force, which acts against the centrifugal force and keep the electrons in there.
(a) Electrostatic force of attraction. (b) Adhesive force
(c) Electromagnetic force of attraction (d) None of the above
114. Which of the following statements is true about the force between two charges?
(a) Unlike charges repel each other
(b) Like charges repel each other
(c) Like charges attract each other
(d) No force exists between two charges.
115. Static electricity is produced by.
(a) Induction (b) friction
(c) Chemical reaction (d) Both induction & friction.
116. Coulomb’s law for the force between two electric charges most closely resembles with
(a) Law of conservation of energy (b) Gauss’s theorem.
(d) Newton’s law of gravitation.
117. On placing a dielectric in an electric field, the field strength
(a) Decreases (b) Increases
(c) Remains the same (d) Reduces to zero.
118. Electric field inside a hollow metallic charged sphere is.
(a) Zero (b) Decreasing towards center.
(c) Increases towards center. (d) None of the above
119. The dielectric strength of the charged conductor
(a) Increases in temperature
(b) Increases with the Increase in thickness.
(c) Increases with moisture content
(d) Is not affected by the moisture content
120. POLERISTATION of dielectric material result in
(a) Production of eddy current (b) Creation of dielectric pole.
(c) Absorption of electron (d) Release of proton
121. Energy stored in a capacitor is given by the expression
(a) W=CV (b) W=1\2CV²
(c) W=iC²V (d) W=2CV²
122.A capacitor of 10(0.F is charged to a Pd the expression
(a) 0.02 J (b) 20 J
(c) 40 J (d) 200 J
123. Resistance of a wire always increases if.
(a) Temperature is reduced (b) Temperature is increased
(c) Number of free electrons available be come less
(e) Number of free electrons available becomes more.
124. There are two wires A & B. A is 20 times longer than B and has half the x-section of that of that of B. if the resistance of B is 1 ft, the resistance of conductor A will be
(a) 40 a (b) 1/40 Q
(c) 20 Q (d) 10 Q
125. The diameter of a wire is reduced to one-half, keeping the length constant. the new resistance will be.
(a) Half of the original (b) 4 time of the original
(c) Double of the original (d) One- fourth of the original
126. A cylindrical metal rod has resistance of 1 ohm it is now reformed to three time its original length what will be resistance.
(a) 1 ohm (b) 2 ohm
(c) 3 ohm (d) 4 ohm
127. The resistance of wire varies inversely as
(a) Area of x-section, (b) Length
(c) Resistivity (d) Temperature
128. The resistance of a conductor increases as
(a) Its length decreases (b) Resistivity decreases
(b) X-sectional area decreases
129. For a fixed supply voltage the current flowing through a conductor will increase when its.
(a) Area of x-section is reduced (b) Length is reduced
(c) Length is increased
(d) Length is increased and x-sectional area is reduced
130. The receptivity or specific resistance is measured in
(a) Ohm-m (b) ohm/m
(c) Ohm/m³ (d) ohm/m²
131. A piece of silver wire has a resistance of l ohm. The resistance of a manganin wire of one-third length and one-third the diameter is if the specific resistance of manganin is 30 time that of silver.
(a) 30 ohm (b) 10ohm
(c) 90 ohm (d) 270 ohm
132. Electrical conductivity is measured in
(a) mho/m (b) mho m
(c) Mho/m³ (d) mho/m²
133. The substance having a large number of free electrons and offering low resistance are called the.
(a) Inductors. (b) Conductors.
(c) Semi Conductors (d) Insulators.
134. With the increase in temperature, the resistance of pure metals.
(a) Increases (b) Decreases.
(c) First increases and then decreases (d) Remains constant
135. With the rise in temperature the resistance of carbon.
(a) Increases (b) decreases
(c) Becomes zero (d) Remains unchanged
136. With the rise in temperature, the temperature coefficient of resistance.
(a) Remains unaffected (b) Increases
(c) Decreases (d) None of these
137. The values of temperature coefficient of resistance of a given conductor.
(a) Are same at different temperature
(b) Are different at different temperature
(c) Are the same
138. The efficiency is defined as ratio of
(a) Input to output, (b) Out put to input
(c) Losses to output, (d) Losses to Input,
139. When a resistance element of a heater gets fused, we remove a portion of it and reconnection it to the same supply, the power drawn by the heater will
(a) Increase (b) Decrease
(d) Remain unchanged
140. A 100 W bulb is connected in series with a room heater if no* 100 W bulb id replaced by a 40 W bulb the heater output will.
(a) Increase (b) Decrease
(d) Remain the same
141. The voltage applied across an electric iron is halved. The power consumption of the iron will reduce to.
(a) One-half (b) Three-fourth
(c) One-fourth (d) 0.707 time
142. For a given line voltage four heating coils will produce maximum heat when connected.
(a) All in parallel (b) All in series
(c) Two parallel pairs in series.
(d) One pair in parallel with the in series.
143. Filament lamp makes use of
(a) Chemical effect (b) Heating effect
(c) Magnetic effect (d) None of these
144. Resistance of a 200 W, 250 V lamp will be.
(a) 625 ohm (b) 1250 ohm
(c) 312.5 ohm (d) 31.25 ohm
145. The cold resistance of a 100 W, 250 V tungsten lamp will be …. While cold resistance of tungsten filament lamp is about one-tenth of the hot resistance
(a) 62.5 ohm (b) 625 ohm
(c) 6,250 ohm (d) None of these
146. For the same voltage, the ratio of resistances of 25 W and 100 W lamps will be.
(a) 1: 1 (b) 2: 1
(c) 1: 2 (c) 1: 4
147. A 1000 W, 240 v electric kettle of heating efficiency 80% of water from 20°C to 100°C .The time required.
(a) 14 minutes (b) 12 minutes
(b) 21 minutes
148.The equivalent resistance of two resistances in series will be.
(a) R1+ R2 (b) 1/R1+R2
(c) R-1R2 (d) None of these
149.Which of the following quantities are the same in all parts of a series circuit?
(a) Voltage (b) Power
(c) Current (d) Resistance
150.Which of the following statements is false in case of a series circuit?
(a) The voltage drop across each resistor is the same
(b) The current flowing through each resistor is the same
(c) Applied voltage is equal to the sum of voltage drops across individual resistors.
(d) Resistors are additive
.