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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
A heating coil is labelled `100 W, 220 V`. The coil is cut in two equal halves and the two pieces are joined in parallel to the same source. The energy now liberated per second isA. 200 JB. 400 JC. 25 JD. 50 J |
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Answer» Correct Answer - B |
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| 52. |
Water boils in an electric kettle in 15 minutes after switching on. If the length of the heating wire is decreased to `2//3` of its initial value, then the same amount of water will with the supply voltage inA. 15 minutesB. 12 minutesC. 10 minutesD. 8 minutes |
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Answer» Correct Answer - C |
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| 53. |
Assertion : If three identical bulbs are connected in series as shown in figure then on closing the switchs. Bulb `C` short circuited and hence illumination of bulbs `A` and `B` decreases. Reason : Voltage on `A` and `B` decreases A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the cor rect explanation of the assertion.C. If assertion is true but reason is falseD. If the assertion and reason both are false |
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Answer» Correct Answer - D |
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| 54. |
Assertion : Electric appliances with metallic body, e.g. heaters, presses etc, have three pin connections, whereas an electric bulb has a two pin connection. Reason : Three pin connection reduce heating of connecting cables.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the cor rect explanation of the assertion.C. If assertion is true but reason is falseD. If the assertion and reason both are false |
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Answer» Correct Answer - C |
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| 55. |
Assertion : In the given circuit if lamp `B` or `C` fuses then light emitted by lamp `A` decreaese. Reason : Voltage on `A` decreases. A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the cor rect explanation of the assertion.C. If assertion is true but reason is falseD. If the assertion and reason both are false |
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Answer» Correct Answer - A |
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| 56. |
An electric kettle has two coils. When one of these is switched on, the water in the kettle boils in 6 minutes. When the other coil is switched on, the water boils in 3 minutes. If the two coils are connected in series, find the time taken to boil the water in the kettle.A. 3 minutesB. 6 minutesC. 2 minutesD. 9 minutes |
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Answer» Correct Answer - D |
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| 57. |
A `3^(0)C` rise in temperature is observed in a conductor by passing a certain current. When the current is doubled, the rise in temp -A. `15^(@)C`B. `12^(@)C`C. `9^(@)C`D. `3^(@)C` |
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Answer» Correct Answer - B |
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| 58. |
Two identical electric lamps marked `500 W`, `220 V` are connected in series and then joined to a `110 V` line. The power consumed by each lamp isA. `(125)/(4)W`B. `(25)/(4)W`C. `(225)/(4)W`D. `125 W` |
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Answer» Correct Answer - A |
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| 59. |
Assertion : Thermocouple acts as a heat engine. Reason : When two junctions of thermocouple are at different temperature, thermo e.m.f. is produced.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the cor rect explanation of the assertion.C. If assertion is true but reason is falseD. If the assertion and reason both are false |
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Answer» Correct Answer - B |
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| 60. |
Assertion : Two bulbs of same wattage, one having a carbon filament and the other having a metallic filament are connected in series. Metallic bulbs will glow more brightly than carbon filament bulb. Reason : Carbon is a semiconductor.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the cor rect explanation of the assertion.C. If assertion is true but reason is falseD. If assertion is false but reason is true. |
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Answer» Correct Answer - D |
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| 61. |
In an electroplating experiment, m gm of silver is deposited when 4 ampere of current flows for 2 minute . The amount (in gm ) of silver deposited by 6 ampere of current for 40 second will beA. 4 mB. m/2C. m/4D. 2 m |
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Answer» Correct Answer - B |
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| 62. |
An electric bulb is designed to draw `P_(0)` power at `V_(0)` voltage. If the voltage is `V`, it drawas power. ThenA. `P=((V_(0))/(V))^(2)P_(0)`B. `P=((V)/(V_(0)))^(2)P_(0)`C. `P=((V)/(V_(0)))P_(0)`D. `P=((V_(0))/(V))P_(0)` |
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Answer» Correct Answer - B |
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| 63. |
A hot electric iron has a resistance of `80 Omega` and is used on a 200 V source. The electrical energy spent, if it is used for two hours, will beA. 8000 WhB. 2000 WhC. 1000 WhD. 800 Wh |
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Answer» Correct Answer - C |
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| 64. |
Calculate the electric current required to deposit `0.972 g` of chromium in three hours. ECE of chromium is `0.00018 g C^(-1)`A. 1 ampB. `1.5 amp`C. `0.5 amp`D. 2 amp |
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Answer» Correct Answer - C |
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| 65. |
You are given three bulbs of 25, 40 and 60 watt . Which of them has lowest resistanceA. 25 watt bulbB. 40 watt bulbC. 60 watt bulbD. Information is insufficient |
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Answer» Correct Answer - C |
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| 66. |
Two electrolytic cells containing `CuSO_(4)` and `AgNO_(3)` respectively are connected in series and a current is passed through them until 1 mg of copper is deposited in the first cell. The amount of silver deposited in the second cell during this time is approximately [Atomic weights of copper and silver are respectively `63.57` and `107.88`]A. `1.7 mg`B. `3.4 mg`C. `5.1 mg`D. `6.8 mg` |
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Answer» Correct Answer - B |
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| 67. |
In an electrolysis experiment, a current i passes through two different cells in series, one containing a solution of `CuSO_(4)` and the other a solution of `AgNO_(3)` . The rate of increase of the weight of the cathodes in the two cells will beA. In the ratio of the densities of Cu and AgB. In the ratio of the at. weights of Cu and AgC. In the ratio of half the atomic weight of Cu to the atomic weight of AgD. In the ratio of half the atomic weight of Cu to half the atomic weight of Ag |
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Answer» Correct Answer - C |
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| 68. |
If a wire of resistance `20 Omega` is covered with ice and a voltage of `210 V` is applied across the wire , then the rate of melting of ice isA. `0.85 g//s`B. `1.92 g//s`C. `6.56 g//s`D. All of these |
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Answer» Correct Answer - C |
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| 69. |
Two heating coils, one of fine wire and the other of thick wire of the same material and of the same length are connected in series and in parallel. Which of the following statement is correct ?A. In series fine wire liberates more energy while in parallel thick wire will liberate more energyB. In series fine wire liberates less energy while in parallel thick wire will liberate more energyC. Both will liberate equallyD. In series the thick wire will liberate more while in parallel it will liberate less energy |
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Answer» Correct Answer - A |
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| 70. |
A wire when connected to `220V` mains sapply power dissipation `P_(1)` Now the wire is cut into two equal pieces which are connected in parallel to the same apply power dissipation in this case is `P_(2)` then `P_(1) : P_(2)` isA. 1B. 4C. 2D. 3 |
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Answer» Correct Answer - B |
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| 71. |
If in the circuit shown in Fig.`7.55`, power dissipation is `150 W` , then find the value of `R ( "in" Omega)`. A. `2 Omega`B. `6 Omega`C. `5 Omega`D. `4 Omega` |
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Answer» Correct Answer - B |
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| 72. |
A `4mu F` conductor is charged to 400 volts and then its plates are joined through a resistance of `1k Omega` . The heat produced in the resistance isA. `0.16 J`B. `1.28 J`C. `0.64 J`D. `0.32 J` |
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Answer» Correct Answer - D |
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| 73. |
For Copper-iron (Cu-Fe) couple, the thermo e.m.f. (temperature of cold junction `=^(@)C`) is given by `E=(14theta-0.02 theta^(2)`) `mu V`. The neutral temperature will beA. `350^(@)C`B. `350 K`C. `560^(@)C`D. `560 K` |
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Answer» Correct Answer - A |
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| 74. |
`e=alpa-(1)/(2)beta t^(2)`, If temperature of cold junction is `0^(@)C` then temperature of inversion is (if `alpha = 500.0 muV//.^(@)C,beta=5.0 mu V//"Square".^(@)C`)A. 100B. 200C. 300D. 400 |
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Answer» Correct Answer - B |
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| 75. |
The electric current passes through a metallic wire produces heat because of :A. Collisions of conduction electrons with each otherB. Collisions of the atoms of the metal with each otherC. The energy released in the ionization of the atoms of the metalD. Collisions of the conduction electrons with the atoms of the metallic wires |
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Answer» Correct Answer - D |
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| 76. |
A current i passes through a wire of length l , radius of cross-section r and resistivity `rho` . The rate of heat generation isA. `(i^(2)l rho)/(pi r^(2))`B. `i^(2)((l rho)/(pi r^(2)))^(2)`C. `i^(2)l rho//r`D. `i l rho//r` |
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Answer» Correct Answer - A |
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| 77. |
If a `30 V, 90 W` bulb is to be worked on a `120 V` line, resistance of how many ohms should be connected in series with the bulbA. 10 ohmB. 20 ohmC. 30 ohmD. 40 ohm |
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Answer» Correct Answer - C |
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| 78. |
If a power of 100 W is being supplied across a potential difference of 200 V , current flowing isA. `2 A`B. `0.5 A`C. `1 A`D. `20 A` |
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Answer» Correct Answer - B |
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| 79. |
Pick out the wrong statementA. In a simple battery circuit, the point of lowest potential is the negative terminal of the batteryB. The resistance of an incandescent lamp is greater when the lamp is switched offC. An ordinary 100 W lamp has less resistance than a 60 W lampD. At constant voltage, the heat developed in a uniform wire varies inversely as the length of the wire used |
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Answer» Correct Answer - B |
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| 80. |
Two resistors of `6 Omega` and `9 Omega` are connected in series to a 120 volt source. The power consumed by the `6 Omega` resistor isA. 384 WB. 576 WC. 1500 WD. 1200 W |
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Answer» Correct Answer - A |
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| 81. |
A 60 watt bulb carries a current of 0.5 amp . The total charge passing through it in 1 hour isA. 3600 coulombB. 3000 coulombC. 2400 coulombD. 1800 coulomb |
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Answer» Correct Answer - D |
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| 82. |
Thomson coefficient of a conductor is `10 mu V//K`. The two ends of it are kept at `50^(@)C` and `60^(@)C` respectively. Amount of heat absorbed by the conductor when a charge of 10 C flows through it isA. 1000 JB. 100 JC. 100 mJD. 1 mJ |
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Answer» Correct Answer - D |
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| 83. |
What will happen when a 40 watt 220 volt lamp and 100 watt-220 volt lamp are connected in series across 40 volt supply?A. 100 watt lamp will fuseB. 40 watt lamp will fuseC. Both lamps will fuseD. Neither lamp will fuse |
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Answer» Correct Answer - D |
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| 84. |
Read the following statements carefully : (i) product of a volt and an ampere is a joude/second (ii) The product of a volt and watt is horse power (iii) The product of a volt and a coulomns is joule (iv) Walt-hour can be measured in terms of electron-voltA. All four are correctB. (1), (2) and (4) are correctC. (1) and (3) are correctD. (3) and (4) are correct |
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Answer» Correct Answer - B |
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| 85. |
A coil takes 15 min to boil a certain amount of water, another coil takes 20 min for the same process. Time taken to boil the same amount of water when both coil are connected in seriesA. 5 minB. `8.6` minC. 35 minD. 30 min |
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Answer» Correct Answer - C |
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| 86. |
3 identical bulbs are connected in series and these together dissipate a power P . If now the bulbs are connected in parallel, then the power dissipated will beA. `(P)/(3)`B. 3PC. 9PD. `(P)/(9)` |
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Answer» Correct Answer - C |
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| 87. |
The current inside a copper voltameterA. Is half the outside valueB. Is the same as the outside valueC. Is twice the outside valueD. Depends on the concentration of `CuSO_(4)` |
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Answer» Correct Answer - B |
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| 88. |
The resistance of a cell does not depend onA. Current drawn from the cellB. Temperature of electrolyteC. Concentration of electrolyteD. The e.m.f . of the cell |
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Answer» Correct Answer - D |
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| 89. |
E.C.E. of Cu and Ag are `7xx10^(-6)` and `1.2xx10^(-6)`. A certain current deposits 14 gm of Cu . Amount of Ag deposited isA. `1.2 gm`B. `1.6 gm`C. `2.4 gm`D. `1.8 gm` |
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Answer» Correct Answer - C |
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| 90. |
In a copper voltameter experiment, current is decreased to one- fourth of the initial value but it is passed for four times the earlier duration. Amount of copper deposited will beA. SameB. One-fourth the previous valueC. Four times the previous valueD. `(1)/(16)th` of the previous value |
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Answer» Correct Answer - A |
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| 91. |
Two bulbs of 500 watt and 200 watt are manufactured to operate on 220 volt line. The ratio of heat produced in `500 W` and `200 W`, in two cases, when firstly they are joined in parallel and secondly in series, will beA. `(5)/(2),(2)/(5)`B. `(5)/(2),(5)/(2)`C. `(2)/(5),(5)/(2)`D. `(2)/(5),(2)/(5)` |
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Answer» Correct Answer - A |
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| 92. |
Three bulbs of 40 W , 60 W , 100 W are arranged in series with 220 volt supply which bulb has minimum resistanceA. 100 WB. 40 WC. 60 WD. Equal in all bulbs |
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Answer» Correct Answer - A |
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| 93. |
Two bulbs of 100 W and 200 W working at 220 volt are joined in series with 220 volt supply. Total power consumed will be approximately.A. 65 wattB. 33 wattC. 300 wattD. 100 watt |
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Answer» Correct Answer - A |
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| 94. |
Two resistors having equal resistances are joined in series and a current is passed through the combination. Neglect any variation in resistance as the temperature changes. In a given time interval,A. Equal amounts of thermal energy must be produced in the resistorsB. Unequal amounts of thermal energy may be producedC. The temperature must rise equally in the resistorsD. The temperature must rise unequally in the resistors |
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Answer» Correct Answer - A |
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| 95. |
An electric heater of resistance 6 ohm is run for 10 minutes on a 120 volt line. The energy liberated in this period of time isA. `7.2xx10^(3)J`B. `14.4xx10^(5) J`C. `43.2xx10^(-4)J`D. `28.8xx10^(4)J` |
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Answer» Correct Answer - B |
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| 96. |
Electric room radiator which operates at 225 volts has resistance of 50 ohms . Power of the radiator is approximatelyA. 100 WB. 450 WC. 750 WD. 1000 W |
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Answer» Correct Answer - D |
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| 97. |
A `500W ` heating unit is designed to operate from a `115 "volt"` line. If the line voltage drop to `110 "Volt"` , the percentage drop in heat output will beA. `10.20%`B. `8.1%`C. `8.6%`D. `7.6%` |
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Answer» Correct Answer - C |
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| 98. |
A 10 ohm electric heater operates on a 110 V line. Calculate the rate at which it develops heat in wattsA. 1310 WB. 670 WC. 810 WD. 1210 W |
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Answer» Correct Answer - D |
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| 99. |
If a given volume of water in a `220 V` heater is boiled in `5 min`, then how much time will it take for the same volume of water in a `110 V` heater to be boiled?A. 5 minutesB. 8 minutesC. 10 minutesD. 20 minutes |
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Answer» Correct Answer - D |
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| 100. |
As the temperature of hot junction increases, the thermo e.m.f.A. Always increasesB. Always decreasesC. May increase or decreaseD. Always remains constant |
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Answer» Correct Answer - C |
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