MCQOPTIONS
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MCQOPTIONS
This section includes 110 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
. The resistivity of a potentiometer wire is \[40\times {{10}^{-8}}\,ohm-m\] and its area of cross-section is \[8\times {{10}^{-6}}\,{{m}^{2}}\]. If 0.2 amp current is flowing through the wire, the potential gradient will be [MP PMT/PET 1998] |
| A. | \[{{10}^{-2}}\,volt/m\] |
| B. | \[{{10}^{-1}}\,volt/m\] |
| C. | \[4\,R\] |
| D. | \[1\,volt/m\] |
| Answer» B. \[{{10}^{-1}}\,volt/m\] | |
| 52. |
The resistance of a galvanometer is 50 ohms and the current required to give full scale deflection is \[100\,\mu A\]. In order to convert it into an ammeter, reading upto 10A, it is necessary to put a resistance of [MP PMT 1997; AIIMS 1999] |
| A. | \[5\times {{10}^{-3}}\,\Omega \] in parallel |
| B. | \[5\times {{10}^{-4}}\,\Omega \] in parallel |
| C. | \[\frac{1}{\rho }\sqrt{3}\] |
| D. | \[99,950\,\Omega \]in series |
| Answer» C. \[\frac{1}{\rho }\sqrt{3}\] | |
| 53. |
A potentiometer circuit shown in the figure is set up to measure e.m.f. of a cell E. As the point P moves from X to Y the galvanometer G shows deflection always in one direction, but the deflection decreases continuously until Y is reached. In order to obtain balance point between X and Y it is necessary to |
| A. | Decreases the resistance R |
| B. | Increase the resistance R |
| C. | \[{{v}_{d}}=\text{constant}\] |
| D. | Reverse the terminals of cell E |
| Answer» B. Increase the resistance R | |
| 54. |
A galvanometer of \[100\,\Omega \] resistance gives full scale deflection when 10 mA of current is passed. To convert it into 10 A range ammeter, the resistance of the shunt required will be [MP PMT 1985] |
| A. | \[-10\,\Omega \] |
| B. | \[1\,\Omega \] |
| C. | 3 : 1 |
| D. | \[0.01\,\Omega \] |
| Answer» D. \[0.01\,\Omega \] | |
| 55. |
AB is a wire of uniform resistance. The galvanometer G shows no current when the length AC = 20cm and CB = 80 cm. The resistance R is equal to [MP PMT 1995; RPET 2001] |
| A. | \[2\,\Omega \] |
| B. | \[8\,\Omega \] |
| C. | For electrolytes when current passes through them |
| D. | \[40\,\Omega \] |
| Answer» D. \[40\,\Omega \] | |
| 56. |
In a potentiometer circuit there is a cell of e.m.f. 2 volt, a resistance of 5 ohm and a wire of uniform thickness of length 1000 cm and resistance 15 ohm. The potential gradient in the wire is [MP PMT 1994] |
| A. | \[\frac{1}{500}V/cm\] |
| B. | \[\frac{3}{2000}V/cm\] |
| C. | The free electrons acquire a constant drift velocity from the lower potential end to the higher potential end of the conductor |
| D. | \[\frac{1}{1000}V/cm\] |
| Answer» C. The free electrons acquire a constant drift velocity from the lower potential end to the higher potential end of the conductor | |
| 57. |
Which is a wrong statement [MP PMT 1994] |
| A. | The Wheatstone bridge is most sensitive when all the four resistances are of the same order |
| B. | In a balanced Wheatstone bridge, interchanging the positions of galvanometer and cell affects the balance of the bridge |
| C. | 10 W |
| D. | The rheostat can be used as a potential divider |
| Answer» C. 10 W | |
| 58. |
A galvanometer of resistance \[25\,\Omega \] gives full scale deflection for a current of 10 milliampere, is to be changed into a voltmeter of range 100 V by connecting a resistance of ?R? in series with galvanometer. The value of resistance R in \[\Omega \] is [MP PET 1994] |
| A. | 10000 |
| B. | 10025 |
| C. | Copper strip increases and that of germanium decreases |
| D. | 9975 |
| Answer» E. | |
| 59. |
A moving coil galvanometer has a resistance of \[50\,\Omega \]and gives full scale deflection for 10 mA. How could it be converted into an ammeter with a full scale deflection for 1A [MP PMT 1996] |
| A. | \[50/99\,\Omega \] in series |
| B. | \[50/99\,\Omega \] in parallel |
| C. | Only negative charge |
| D. | \[0.01\,\Omega \] in parallel |
| Answer» C. Only negative charge | |
| 60. |
A voltmeter has a resistance of G ohms and range V volts. The value of resistance used in series to convert it into a voltmeter of range nV volts is [MP PMT 1999; MP PET 2002; DPMT 2004; MH CET 2004] |
| A. | nG |
| B. | \[(n-1)G\] |
| C. | 1 : 8 |
| D. | \[\frac{G}{(n-1)}\] |
| Answer» C. 1 : 8 | |
| 61. |
The resistance of a galvanometer is 90 ohms. If only 10 percent of the main current may flow through the galvanometer, in which way and of what value, a resistor is to be used [MP PET 1996] |
| A. | 10 ohms in series |
| B. | 10 ohms in parallel |
| C. | 6.25 × \[{{10}^{31}}\] |
| D. | 810 ohms in parallel |
| Answer» C. 6.25 × \[{{10}^{31}}\] | |
| 62. |
In potentiometer a balance point is obtained, when |
| A. | The e.m.f. of the battery becomes equal to the e.m.f. of the experimental cell |
| B. | The p.d. of the wire between the +ve end to becomes equal to the e.m.f. of the experimental cell |
| C. | Will remain the same |
| D. | The p.d. across the potentiometer wire becomes equal to the e.m.f. of the battery |
| Answer» C. Will remain the same | |
| 63. |
A galvanometer of 10 ohm resistance gives full scale deflection with 0.01 ampere of current. It is to be converted into an ammeter for measuring 10 ampere current. The value of shunt resistance required will be [MP PET 1984] |
| A. | \[\frac{10}{999}\]ohm |
| B. | 0.1 ohm |
| C. | 220 volts |
| D. | 1.0 ohm |
| Answer» B. 0.1 ohm | |
| 64. |
Sensitivity of potentiometer can be increased by [MP PET 1994] |
| A. | Increasing the e.m.f. of the cell |
| B. | Increasing the length of the potentiometer wire |
| C. | 4 W, 1.0 amp |
| D. | None of the above |
| Answer» C. 4 W, 1.0 amp | |
| 65. |
A galvanometer can be converted into an ammeter by connecting [MP PMT 1987, 93; CPMT 1973, 75, 96, 2000; MP PET 1994; AFMC 1993, 95; RPET 2000; DCE 2000] |
| A. | Low resistance in series |
| B. | High resistance in parallel |
| C. | \[6000\,\Omega \] |
| D. | High resistance in series |
| Answer» D. High resistance in series | |
| 66. |
When a \[12\,\Omega \] resistor is connected with a moving coil galvanometer then its deflection reduces from 50 divisions to 10 divisions. The resistance of the galvanometer is [CPMT 2002; DPMT 2003] |
| A. | \[24\,\Omega \] |
| B. | \[36\,\Omega \] |
| C. | 0.02 V/cm |
| D. | \[60\,\Omega \] |
| Answer» D. \[60\,\Omega \] | |
| 67. |
With a potentiometer null point were obtained at 140 cm and 180 cm with cells of emf 1.1 V and one unknown X volts. Unknown emf is [DCE 2002] |
| A. | 1.1 V |
| B. | 1.8 V |
| C. | 0.1 |
| D. | 1.41 V |
| Answer» E. | |
| 68. |
In given figure, the potentiometer wire AB has a resistance of 5 W and length 10 m. The balancing length AM for the emf of 0.4 V is [Pb. PET 2001] |
| A. | 0.4 m |
| B. | 4 m |
| C. | \[0.62\times {{10}^{-4}}\,V/mm\] |
| D. | 8 m |
| Answer» E. | |
| 69. |
A galvanometer coil of resistance 50 W, show full deflection of \[100\mu A\]. The shunt resistance to be added to the galvanometer, to work as an ammeter of range 10 mA is [Pb PET 2000] |
| A. | 5 W in parallel |
| B. | 0.5 W in series |
| C. | 0.2 amp |
| D. | 0.5 W in parallel |
| Answer» E. | |
| 70. |
The maximum current that can be measured by a galvanometer of resistance 40 W is 10 mA. It is converted into a voltmeter that can read upto 50 V. The resistance to be connected in series with the galvanometer is ... (in ohm) [KCET 2004] |
| A. | 5040 |
| B. | 4960 |
| C. | \[0.4\,\Omega \] |
| D. | 4050 |
| Answer» C. \[0.4\,\Omega \] | |
| 71. |
The e.m.f. of a standard cell balances across 150 cm length of a wire of potentiometer. When a resistance of \[2\,\Omega \] is connected as a shunt with the cell, the balance point is obtained at \[100\,cm\]. The internal resistance of the cell is [MP PET 1993] |
| A. | \[0.1\,\Omega \] |
| B. | \[1\,\Omega \] |
| C. | \[5\,V/m\] |
| D. | \[0.5\,\Omega \] |
| Answer» C. \[5\,V/m\] | |
| 72. |
A galvanometer, having a resistance of 50 W gives a full scale deflection for a current of 0.05 A. The length in meter of a resistance wire of area of cross-section 2.97× 10?2 cm2 that can be used to convert the galvanometer into an ammeter which can read a maximum of 5 A current is (Specific resistance of the wire = 5 × \[{{10}^{-7}}\]Wm) [EAMCET 2003] |
| A. | 9 |
| B. | 6 |
| C. | \[420\,k\Omega \] |
| D. | 1.5 |
| Answer» D. 1.5 | |
| 73. |
Two resistances of 400 W and 800 W are connected in series with 6 volt battery of negligible internal resistance. A voltmeter of resistance 10,000 W is used to measure the potential difference across 400 W. The error in the measurement of potential difference in volts approximately is [EAMCET 2003] |
| A. | 0.01 |
| B. | 0.02 |
| C. | \[3.2\times {{10}^{-2}}\,volt/m\] |
| D. | 0.05 |
| Answer» E. | |
| 74. |
A 50 ohm galvanometer gets full scale deflection when a current of 0.01 A passes through the coil. When it is converted to a 10 A ammeter, the shunt resistance is [Orissa JEE 2003] |
| A. | 0.01 W |
| B. | 0.05 W |
| C. | Reverse the terminals of battery V |
| D. | 5000 W |
| Answer» C. Reverse the terminals of battery V | |
| 75. |
For measurement of potential difference, potentiometer is preferred in comparison to voltmeter because [MP PET 1983] |
| A. | Potentiometer is more sensitive than voltmeter |
| B. | The resistance of potentiometer is less than voltmeter |
| C. | \[0.1\,\Omega \] |
| D. | Potentiometer does not take current from the circuit |
| Answer» E. | |
| 76. |
The potential difference across the 100W resistance in the following circuit is measured by a voltmeter of 900 W resistance. The percentage error made in reading the potential difference is [AMU (Med.) 2002] |
| A. | \[\frac{10}{9}\] |
| B. | 0.1 |
| C. | \[20\,\Omega \] |
| D. | 10 |
| Answer» D. 10 | |
| 77. |
A potentiometer has uniform potential gradient across it. Two cells connected in series (i) to support each other and (ii) to oppose each other are balanced over 6m and 2m respectively on the potentiometer wire. The e.m.f.?s of the cells are in the ratio of [MP PMT 2002] |
| A. | 1 : 2 |
| B. | 0.042361111111111 |
| C. | Voltmeter has low resistance and is connected in parallel |
| D. | 0.084027777777778 |
| Answer» E. | |
| 78. |
There are three voltmeters of the same range but of resistances \[10000\,\Omega \], \[8000\,\Omega \] and \[4000\,\Omega \] respectively. The best voltmeter among these is the one whose resistance is [Kerala PET 2002] |
| A. | 10000 W |
| B. | 8000 W |
| C. | \[\frac{3}{5000}V/cm\] |
| D. | All are equally good |
| Answer» B. 8000 W | |
| 79. |
A wire of length 100 cm is connected to a cell of emf 2 V and negligible internal resistance. The resistance of the wire is 3 W. The additional resistance required to produce a potential drop of 1 milli volt per cm is [Kerala PET 2002] |
| A. | 60 W |
| B. | 47 W |
| C. | Kirchhoff's first law (for currents meeting at a junction in an electric circuit) expresses the conservation of charge |
| D. | 35 W |
| Answer» D. 35 W | |
| 80. |
The measurement of voltmeter in the following circuit is [AFMC 2001] |
| A. | 2.4 V |
| B. | 3.4 V |
| C. | 975 |
| D. | 6.0 V |
| Answer» E. | |
| 81. |
In Meter Bridge or Wheatstone bridge for measurement of resistance, the known and the unknown resistances are interchanged. The error so removed is [MNR 1988; MP PET 1995] |
| A. | End correction |
| B. | Index error |
| C. | \[0.01\,\Omega \] in series |
| D. | Random error |
| Answer» B. Index error | |
| 82. |
The resistance of a heater coil is 110 ohm. A resistance R is connected in parallel with it and the combination is joined in series with a resistance of 11 ohm to a 220 volt main line. The heater operates with a power of 110 watt. The value of R in ohm is [ISM Dhanbad 1994] |
| A. | 12.22 |
| B. | 24.42 |
| C. | \[\frac{G}{n}\] |
| D. | That the given values are not correct |
| Answer» B. 24.42 | |
| 83. |
In the circuit of adjoining figure the current through 12 W resister will be |
| A. | 1 A |
| B. | \[\frac{1}{5}A\] |
| C. | 810 ohms in series |
| D. | 0 A |
| Answer» E. | |
| 84. |
For ensuring dissipation of same energy in all three resistors \[({{R}_{1}},\,{{R}_{2}},\,{{R}_{3}})\] connected as shown in figure, their values must be related as ] [AIIMS 2005] |
| A. | \[{{R}_{1}}={{R}_{2}}={{R}_{3}}\] |
| B. | \[{{R}_{2}}={{R}_{3}}\]and \[{{R}_{1}}=4{{R}_{2}}\] |
| C. | The p.d. of the wire between +ve point and jockey becomes equal to the e.m.f. of the battery |
| D. | \[{{R}_{1}}={{R}_{2}}+{{R}_{3}}\] |
| Answer» D. \[{{R}_{1}}={{R}_{2}}+{{R}_{3}}\] | |
| 85. |
A thermo couple uses Bismuth and Tellurium as the dissimilar metals. The sensitivity of bismuth is \[-\,72\mu \,V{{/}^{o}}C\] and that of the tellurium is \[500\mu \,\,V{{/}^{o}}C\]. If the difference between hot and cold junction is \[{{100}^{o}}C,\] then the maximum output will be |
| A. | \[50\,\,mV\] |
| B. | \[7.2\,\,mV\] |
| C. | 0.5 ohm |
| D. | \[57.2\,\,mV\] |
| Answer» E. | |
| 86. |
The emf of a thermocouple, one junction of which is kept at \[{{0}^{o}}C,\] is given by \[e=at+b{{t}^{2}}\] the Peltier co-efficient will be |
| A. | \[(t+273)\,\,(a+2bt)\] |
| B. | \[(t+273)\,\,(a-2bt)\] |
| C. | Decreasing the length of the potentiometer wire |
| D. | \[(t-273)\,\,(a-2bt)\] |
| Answer» B. \[(t+273)\,\,(a-2bt)\] | |
| 87. |
A thermocouple of resistance \[1.6\,\Omega \] is connected in series with a galvanometer of \[8\,\Omega \] resistance. The thermocouple develops and e.m.f. of \[10\mu V\] per degree temperature difference between two junctions. When one junction is kept at \[{{0}^{o}}C\] and the other in a molten metal, the galvanometer reads 8 millivolt. The temperature of molten metal, when e.m.f. varies linearly with temperature difference, will be |
| A. | \[{{960}^{o}}C\] |
| B. | \[{{1050}^{o}}C\] |
| C. | Low resistance in parallel |
| D. | \[{{1545}^{o}}C\] |
| Answer» B. \[{{1050}^{o}}C\] | |
| 88. |
An ammeter, suspected to give inaccurate reading, is connected in series with a silver voltameter. The ammeter indicates 0.54 A. A steady current passed for one hour deposits 2.0124 gm of silver. If the E.C.E. of silver is \[1.118\times {{10}^{-3}}\,gm{{C}^{-1}},\] then the error in ammeter reading is |
| A. | + 0.04 A |
| B. | + 0.02 A |
| C. | \[48\,\Omega \] |
| D. | ? 0.01 A |
| Answer» B. + 0.02 A | |
| 89. |
The effective resistance between points P and Q of the electrical circuit shown in the figure is [IIT-JEE (Screening) 2002] |
| A. | \[2Rr/(R+r)\] |
| B. | \[8R\,(R+r)/(3R+r)\] |
| C. | 2.4 V |
| D. | \[5R/2\,\,+\,2r\] |
| Answer» B. \[8R\,(R+r)/(3R+r)\] | |
| 90. |
What is the equivalent resistance between the points A and B of the network [AMU (Engg.) 2001] |
| A. | \[\frac{57}{7}\Omega \] |
| B. | 8 W |
| C. | 0.8 m |
| D. | \[\frac{57}{5}\Omega \] |
| Answer» C. 0.8 m | |
| 91. |
A thermo couple develops \[200\,\mu \,V\] between \[{{0}^{o}}C\] and \[{{100}^{o}}C.\] If it develops \[64\,\,\mu \,V\] and \[76\,\mu \,V\] respectively between \[({{0}^{o}}C-{{32}^{o}}C)\] and \[({{32}^{o}}C-{{70}^{o}}C)\]then what will be the thermo emf it develops between \[{{70}^{o}}C\] and \[{{100}^{o}}C\] |
| A. | \[65\,\,\mu \,V\] |
| B. | \[60\,\,\mu V\] |
| C. | 5 W in series |
| D. | \[50\,\,\mu V\] |
| Answer» C. 5 W in series | |
| 92. |
A microammeter has a resistance of \[100\,\Omega \] and full scale range of \[50\,\mu A\]. It can be used as a voltmeter or as a higher range ammeter provided a resistance is added to it. Pick the correct range and resistance combination [SCRA 1996; AMU (Med.) 2001; Roorkee 2000] |
| A. | 50 V range with \[10\,k\Omega \] resistance in series |
| B. | 10 V range with \[200\,k\Omega \] resistance in series |
| C. | 2010 |
| D. | 10 mA range with \[0.1\,\Omega \] resistance in parallel |
| Answer» C. 2010 | |
| 93. |
A silver voltameter of resistance 2 ohm and a 3 ohm resistor are connected in series across a cell. If a resistance of 2 ohm is connected in parallel with the voltameter, then the rate of deposition of silver [EAMCET 1983] |
| A. | Decreases by 25% |
| B. | Increases by 25% |
| C. | \[2\,\Omega \] |
| D. | Decreases by 37.5% |
| Answer» E. | |
| 94. |
Two cells of equal e.m.f. and of internal resistances \[{{r}_{1}}\] and \[{{r}_{2}}({{r}_{1}}>{{r}_{2}})\] are connected in series. On connecting this combination to an external resistance R, it is observed that the potential difference across the first cell becomes zero. The value of R will be [MP PET 1985; KCET 2005; Kerala PMT 2005] |
| A. | \[{{r}_{1}}+{{r}_{2}}\] |
| B. | \[{{r}_{1}}-{{r}_{2}}\] |
| C. | 3 |
| D. | \[\frac{{{r}_{1}}-{{r}_{2}}}{2}\] |
| Answer» C. 3 | |
| 95. |
Two wires of resistance R1 and R2 have temperature coefficient of resistance \[{{\alpha }_{1}}\text{ and }{{\alpha }_{2}}\], respectively. These are joined in series. The effective temperature coefficient of resistance is [MP PET 2003] |
| A. | \[\frac{{{\alpha }_{1}}+{{\alpha }_{2}}}{2}\] |
| B. | \[\sqrt{{{\alpha }_{1}}{{\alpha }_{2}}}\] |
| C. | 0.03 |
| D. | \[\frac{\sqrt{{{R}_{1}}{{R}_{2}}{{\alpha }_{1}}{{\alpha }_{2}}}}{\sqrt{R_{1}^{2}+R_{2}^{2}}}\] |
| Answer» D. \[\frac{\sqrt{{{R}_{1}}{{R}_{2}}{{\alpha }_{1}}{{\alpha }_{2}}}}{\sqrt{R_{1}^{2}+R_{2}^{2}}}\] | |
| 96. |
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 is [AFMC 1997] |
| A. | \[0.85\,g/s\] |
| B. | \[1.92\,g/s\] |
| C. | \[\frac{1}{140}\] |
| D. | All of these |
| Answer» D. All of these | |
| 97. |
For goldplating on a copper chain, the substance required in the form of solution is |
| A. | Copper sulphate |
| B. | Copper chloride |
| C. | 2000 W |
| D. | Potassium aurocyanide |
| Answer» E. | |
| 98. |
E.C.E. of Cu and Ag are \[7\times {{10}^{-6}}\] and \[1.2\times {{10}^{-6}}.\]A certain current deposits 14 gm of Cu. Amount of Ag deposited is [Orissa PMT 2004] |
| A. | 1.2 gm |
| B. | 1.6 gm |
| C. | Potentiometer is cheaper than voltmeter |
| D. | 1.8 gm |
| Answer» D. 1.8 gm | |
| 99. |
How much current should be passed through acidified water for 100 s to liberate 0.224 litre of \[{{H}_{2}}\] [DCE 2002] |
| A. | 22.4 A |
| B. | \[19.3\,\,A\] |
| C. | 1 |
| D. | 1 A |
| Answer» C. 1 | |
| 100. |
The electrochemical equivalent of a material in an electrolyte depends on [MP PET 2001] |
| A. | The nature of the material |
| B. | The current through the electrolyte |
| C. | 0.12569444444444 |
| D. | The amount of material present in electrolyte |
| Answer» B. The current through the electrolyte | |