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.
| 1. |
A galvanometer of resistance 36 W is changed into an ammeter by using a shunt of 4 W. The fraction f0 of total current passing through the galvanometer is [BCECE 2003] |
| A. | \[\frac{1}{40}\] |
| B. | \[\frac{1}{4}\] |
| C. | \[{{10}^{5}}\,\Omega \] in series |
| D. | \[\frac{1}{10}\] |
| Answer» E. | |
| 2. |
The resistance\[{{R}_{t}}\] of a conductor varies with temperature t as shown in the figure. If the variation is represented by \[{{R}_{t}}={{R}_{0}}[1+\alpha t+\beta {{t}^{2}}]\], then [CPMT 1988] |
| A. | \[\alpha \] and \[\beta \] are both negative |
| B. | \[\alpha \] and \[\beta \] are both positive |
| C. | 10 units |
| D. | \[\alpha \] is negative and \[\beta \] are positive |
| Answer» C. 10 units | |
| 3. |
The V-i graphs A and B drawn for two voltameters. Identify each graph |
| A. | A for water voltameter and B for \[Cu\] voltameter |
| B. | A for \[Cu\] voltameter and B for water voltameter |
| C. | both microscope and telescope) |
| D. | None of these |
| Answer» B. A for \[Cu\] voltameter and B for water voltameter | |
| 4. |
The graph which represents the relation between the total resistance R of a multi range moving coil voltmeter and its full scale deflection V is |
| A. | (i) |
| B. | (ii) |
| C. | Real, not magnified |
| D. | (iv) |
| Answer» E. | |
| 5. |
In a copper voltameter, mass deposited in 30 second is m gm. If the time-current graph is as shown in figure, ECE of copper is |
| A. | m |
| B. | \[m/2\] |
| C. | + 0. 8D |
| D. | 0.6 m |
| Answer» C. + 0. 8D | |
| 6. |
The resistance of a 5 cm long wire is 10 W. It is uniformly stretched so that its length becomes 20 cm. The resistance of the wire is [MH CET 2002] |
| A. | 160 W |
| B. | 80 W |
| C. | Wavelength and frequency only |
| D. | 20 W |
| Answer» B. 80 W | |
| 7. |
Calculate the amount of charge flowing in 2 minutes in a wire of resistance 10 W when a potential difference of 20 V is applied between its ends [Kerala (Engg.) 2001] |
| A. | 120 C |
| B. | 240 C |
| C. | total internal reflection of light |
| D. | 4 C |
| Answer» C. total internal reflection of light | |
| 8. |
If potential \[V=100\pm 0.5\,Volt\] and current \[I=10\pm 0.2\] amp are given to us. Then what will be the value of resistance [RPET 2001] |
| A. | \[10\pm 0.7\,ohm\] |
| B. | \[5\pm 2\,ohm\] |
| C. | thermal power radiated by the circuit |
| D. | None of these |
| Answer» E. | |
| 9. |
At what temperature will the resistance of a copper wire become three times its value at 0oC (Temperature coefficient of resistance for copper = 4 × 10?3 per oC ) [MP PET 2000] |
| A. | \[{{400}^{o}}C\] |
| B. | \[{{450}^{o}}C\] |
| C. | conductor |
| D. | \[{{550}^{o}}C\] |
| Answer» D. \[{{550}^{o}}C\] | |
| 10. |
An electron (charge = 1.6 × 10?19 coulomb) is moving in a circle of radius 5.1 × 10?11m at a frequency of 6.8 × 1015 revolutions/sec. The equivalent current is approximately [MP PET 2000] |
| A. | \[5.1\times {{10}^{-3}}\] amp |
| B. | \[6.8\times {{10}^{-3}}\] amp |
| C. | 1, 2 and 4 only |
| D. | \[2.2\times {{10}^{-3}}\] amp |
| Answer» D. \[2.2\times {{10}^{-3}}\] amp | |
| 11. |
Conductivity increases in the order of [AFMC 2000] |
| A. | Al, Ag, Cu |
| B. | Al, Cu, Ag |
| C. | be of different materials |
| D. | Ag, Cu, Al |
| Answer» C. be of different materials | |
| 12. |
The resistivity of iron is\[1\times {{10}^{-7}}\,ohm-m\]. The resistance of a iron wire of particular length and thickness is 1 ohm. If the length and the diameter of wire both are doubled, then the resistivity in \[ohm-m\] will be [CPMT 1983; DPMT 1999] |
| A. | \[1\times {{10}^{-7}}\] |
| B. | \[2\times {{10}^{-7}}\] |
| C. | A-2, B-1, C-4, D-3 |
| D. | \[8\times {{10}^{-7}}\] |
| Answer» B. \[2\times {{10}^{-7}}\] | |
| 13. |
If an electric current is passed through a nerve of a man, then man [UPSEAT 1999] |
| A. | Begins to laugh |
| B. | Begins to weep |
| C. | Moisture in the upper layers of atmosphere prevents them from reaching the surface of the Earth |
| D. | Becomes insensitive to pain |
| Answer» D. Becomes insensitive to pain | |
| 14. |
Two rods of same material and length have their electric resistance in ratio \[1:2\]. When both rods are dipped in water, the correct statement will be [RPMT 1997] |
| A. | A has more loss of weight |
| B. | B has more loss of weight |
| C. | reduces current in the circuit |
| D. | Loss of weight will be in the ratio \[1:2\] |
| Answer» B. B has more loss of weight | |
| 15. |
The specific resistance of managing is \[50\times {{10}^{-8}}\,ohm\times m\]. The resistance of a cube of length \[50\,cm\] will be |
| A. | \[{{10}^{-6}}\,ohm\] |
| B. | \[2.5\times {{10}^{-5}}\,ohm\] |
| C. | Steel, brass and rubber respectively |
| D. | \[5\times {{10}^{-4}}\,ohm\] |
| Answer» B. \[2.5\times {{10}^{-5}}\,ohm\] | |
| 16. |
A platinum resistance thermometer has a resistance of \[50\,\Omega \] at \[20{}^\circ C\]. When dipped in a liquid the resistance becomes \[76.8\,\Omega \]. The temperature coefficient of resistance for platinum is \[\alpha =3.92\times {{10}^{-3}}/{}^\circ C\]. The temperature of the liquid is |
| A. | \[100{}^\circ C\] |
| B. | \[137{}^\circ C\] |
| C. | Clock used needed regulating |
| D. | \[200{}^\circ C\] |
| Answer» D. \[200{}^\circ C\] | |
| 17. |
If a 0.1 % increase in length due to stretching, the percentage increase in its resistance will be [MNR 1990; MP PMT 1996; UPSEAT 1999; MP PMT 2000] |
| A. | 0.2 % |
| B. | 0.02 |
| C. | \[\frac{S}{2Y}\] |
| D. | 0.001 |
| Answer» B. 0.02 | |
| 18. |
The reciprocal of resistance is [AFMC 1995] |
| A. | Conductance |
| B. | Resistivity |
| C. | 0.12638888888889 |
| D. | None of the above |
| Answer» B. Resistivity | |
| 19. |
Resistance of tungsten wire at \[150{}^\circ C\] is \[133\,\Omega \]. Its resistance temperature coefficient is \[0.0045/{}^\circ C\]. The resistance of this wire at \[500{}^\circ C\] will be [DPMT 2004] |
| A. | \[180\,\Omega \] |
| B. | \[225\,\Omega \] |
| C. | 0.025 cc |
| D. | \[317\,\Omega \] |
| Answer» D. \[317\,\Omega \] | |
| 20. |
A certain piece of silver of given mass is to be made like a wire. Which of the following combination of length (L) and the area of cross-sectional will lead to the smallest resistance [MP PMT 1995; CBSE PMT 1997] |
| A. | L and A |
| B. | 2L and A/2 |
| C. | 51.2 ´ 105 Pa |
| D. | Any of the above, because volume of silver remains same |
| Answer» D. Any of the above, because volume of silver remains same | |
| 21. |
An electric wire of length ?I? and area of cross-section \[a\] has a resistance R ohms. Another wire of the same material having same length and area of cross-section 4a has a resistance of [MP PMT 1993] |
| A. | 4R |
| B. | R/4 |
| C. | \[\gamma \times \]pressure |
| D. | 16R |
| Answer» C. \[\gamma \times \]pressure | |
| 22. |
The electric intensity \[E\], current density \[j\] and specific resistance \[k\] are related to each other by the relation [DPMT 2001] |
| A. | \[E=j/k\] |
| B. | \[E=jk\] |
| C. | Is equal to its pressure p |
| D. | \[k=jE\] |
| Answer» C. Is equal to its pressure p | |
| 23. |
The positive temperature coefficient of resistance is for |
| A. | Carbon |
| B. | Germanium |
| C. | Maxwell |
| D. | An electrolyte |
| Answer» D. An electrolyte | |
| 24. |
When current flows through a conductor, then the order of drift velocity of electrons will be [CPMT 1986] |
| A. | \[{{10}^{10}}\,m/\sec \] |
| B. | \[{{10}^{-2}}\,cm/\sec \] |
| C. | If assertion is true but reason is false. |
| D. | \[{{10}^{-1}}\,cm/\sec \] |
| Answer» C. If assertion is true but reason is false. | |
| 25. |
In an electrolyte \[3.2\times {{10}^{18}}\] bivalent positive ions drift to the right per second while \[3.6\times {{10}^{18}}\] monovalent negative ions drift to the left per second. Then the current is |
| A. | 1.6 amp to the left |
| B. | 1.6 amp to the right |
| C. | \[\alpha \] is positive and \[\beta \] is negative |
| D. | 0.45 amp to the left |
| Answer» C. \[\alpha \] is positive and \[\beta \] is negative | |
| 26. |
When the current \[i\] is flowing through a conductor, the drift velocity is \[v\]. If \[2i\] current is flowed through the same metal but having double the area of cross-section, then the drift velocity will be |
| A. | \[v/4\] |
| B. | \[v/2\] |
| C. | Both A and B represents \[Cu\] voltameter |
| D. | \[4v\] |
| Answer» D. \[4v\] | |
| 27. |
When there is an electric current through a conducting wire along its length, then an electric field must exist |
| A. | Outside the wire but normal to it |
| B. | Outside the wire but parallel to it |
| C. | (iii) |
| D. | Inside the wire but normal to it |
| Answer» D. Inside the wire but normal to it | |
| 28. |
A certain wire has a resistance \[R\]. The resistance of another wire identical with the first except having twice its diameter is [CPMT 1999] |
| A. | \[2\,R\] |
| B. | \[0.25\,R\] |
| C. | 0.1 m |
| D. | \[0.5\,R\] |
| Answer» C. 0.1 m | |
| 29. |
The specific resistance of a wire is \[\rho \], its volume is 3\[{{m}^{3}}\] and its resistance is 3 ohms, then its length will be [CPMT 1984] |
| A. | \[\sqrt{\frac{1}{\rho }}\] |
| B. | \[\frac{3}{\sqrt{\rho }}\] |
| C. | 40 W |
| D. | \[\rho \sqrt{\frac{1}{3}}\] |
| Answer» C. 40 W | |
| 30. |
Drift velocity \[{{v}_{d}}\] varies with the intensity of electric field as per the relation [CPMT 1981; BVP 2003] |
| A. | \[{{v}_{d}}\propto E\] |
| B. | \[{{v}_{d}}\propto \frac{1}{E}\] |
| C. | 20 C |
| D. | \[{{v}_{d}}\propto {{E}^{2}}\] |
| Answer» B. \[{{v}_{d}}\propto \frac{1}{E}\] | |
| 31. |
A thick wire is stretched so that its length become two times. Assuming that there is no change in its density, then what is the ratio of change in resistance of wire to the initial resistance of wire [MH CET 2004] |
| A. | 2 : 1 |
| B. | 4 : 1 |
| C. | \[0.1\pm 0.2ohm\] |
| D. | 1 : 4 |
| Answer» D. 1 : 4 | |
| 32. |
Ohm's law is true |
| A. | For metallic conductors at low temperature |
| B. | For metallic conductors at high temperature |
| C. | \[{{500}^{o}}C\] |
| D. | For diode when current flows |
| Answer» B. For metallic conductors at high temperature | |
| 33. |
A wire of diameter 0.02 metre contains 1028 free electrons per cubic metre. For an electrical current of 100 A, the drift velocity of the free electrons in the wire is nearly [UPSEAT 2004] |
| A. | \[1\times {{10}^{19}}m/s\] |
| B. | \[5\times {{10}^{10}}m/s\] |
| C. | \[1.1\times {{10}^{-3}}\] amp |
| D. | \[8\times {{10}^{3}}m/s\] |
| Answer» D. \[8\times {{10}^{3}}m/s\] | |
| 34. |
When a potential difference is applied across the ends of a linear metallic conductor [MP PET 1997] |
| A. | The free electrons are accelerated continuously from the lower potential end to the higher potential end of the conductor |
| B. | The free electrons are accelerated continuously from the higher potential end to the lower potential end of the conductor |
| C. | Cu, Al, Ag |
| D. | The free electrons are set in motion from their position of rest |
| Answer» D. The free electrons are set in motion from their position of rest | |
| 35. |
What is the resistance of a carbon resistance which has bands of colours brown, black and brown [DCE 1999] |
| A. | 100 W |
| B. | 1000 W |
| C. | \[4\times {{10}^{-7}}\] |
| D. | 1 W |
| Answer» B. 1000 W | |
| 36. |
A strip of copper and another of germanium are cooled from room temperature to 80 K. The resistance of [AIEEE 2003] |
| A. | Each of these increases |
| B. | Each of these decreases |
| C. | Is excited |
| D. | Copper strip decreases and that of germanium increases |
| Answer» E. | |
| 37. |
A steady current i is flowing through a conductor of uniform cross-section. Any segment of the conductor has [MP PET 1996] |
| A. | Zero charge |
| B. | Only positive charge |
| C. | Both have same loss of weight |
| D. | Charge proportional to current i |
| Answer» B. Only positive charge | |
| 38. |
Two wires of same material have length L and 2L and cross?sectional areas 4A and A respectively. The ratio of their specific resistance would be [MHCET 2002] |
| A. | 1 : 2 |
| B. | 8 : 1 |
| C. | \[{{10}^{-8}}\,ohm\] |
| D. | 1 : 1 |
| Answer» E. | |
| 39. |
A current of 1 mA is flowing through a copper wire. How many electrons will pass a given point in one second \[\left[ e=\text{ }1.6\text{ }\times \text{ }{{10}^{19}}Coulomb \right]\] [RPMT 2000; MP PMT 2002] |
| A. | 6.25 × \[{{10}^{19}}\] |
| B. | 6.25 × \[{{10}^{15}}\] |
| C. | \[167{}^\circ C\] |
| D. | 6.25 × \[{{10}^{8}}\] |
| Answer» C. \[167{}^\circ C\] | |
| 40. |
When the length and area of cross-section both are doubled, then its resistance [MP PET 1989] |
| A. | Will become half |
| B. | Will be doubled |
| C. | 0.01 |
| D. | Will become four times |
| Answer» D. Will become four times | |
| 41. |
Voltmeters V1 and V2 are connected in series across a D.C. line. V1 reads 80 volts and has a per volt resistance of 200 ohms. V2 has a total resistance of 32 kilo ohms. The line voltage is [UPSEAT 2000] |
| A. | 120 volts |
| B. | 160 volts |
| C. | Voltage |
| D. | 240 volts |
| Answer» E. | |
| 42. |
In the circuit shown, a meter bridge is in its balanced state. The meter bridge wire has a resistance 0.1 ohm/cm. The value of unknown resistance X and the current drawn from the battery of negligible resistance is [AMU (Engg.) 2000] |
| A. | 6 W, 5 amp |
| B. | 10 W, 0.1 amp |
| C. | \[258\,\Omega \] |
| D. | 12 W, 0.5 amp |
| Answer» D. 12 W, 0.5 amp | |
| 43. |
A voltmeter has resistance of 2000 ohms and it can measure upto 2V. If we want to increase its range to 10 V, then the required resistance in series will be [CPMT 1997, SCRA 1994] |
| A. | \[2000\,\Omega \] |
| B. | \[4000\,\Omega \] |
| C. | L/2 and 2 A |
| D. | \[8000\,\Omega \] |
| Answer» E. | |
| 44. |
A 2 volt battery, a \[15\,\Omega \] resistor and a potentiometer of 100 cm length, all are connected in series. If the resistance of potentiometer wire is \[5\,\Omega \], then the potential gradient of the potentiometer wire is [AIIMS 1982] |
| A. | 0.005 V/cm |
| B. | 0.05 V/cm |
| C. | R/16 |
| D. | 0.2 V/cm |
| Answer» B. 0.05 V/cm | |
| 45. |
An ammeter whose resistance is \[180\,\Omega \] gives full scale deflection when current is 2 mA. The shunt required to convert it into an ammeter reading 20 mA (in ohms) is [EAMCET (Engg.) 1995] |
| A. | 18 |
| B. | 20 |
| C. | \[E=k/j\] |
| D. | 10 |
| Answer» C. \[E=k/j\] | |
| 46. |
A potentiometer wire has length 10 m and resistance \[20\,\Omega \]. A 2. 5 V battery of negligible internal resistance is connected across the wire with an \[80\,\Omega \] series resistance. The potential gradient on the wire will be [KCET 1994] |
| A. | \[5\times {{10}^{-5}}\,V/mm\] |
| B. | \[2.5\times {{10}^{-4}}\,V/cm\] |
| C. | Copper |
| D. | \[1\times {{10}^{-5}}\,V/mm\] |
| Answer» B. \[2.5\times {{10}^{-4}}\,V/cm\] | |
| 47. |
A galvanometer having a resistance of 8 ohm is shunted by a wire of resistance 2 ohm. If the total current is 1 amp, the part of it passing through the shunt will be [CBSE PMT 1998] |
| A. | 0.25 amp |
| B. | 0.8 amp |
| C. | \[{{10}^{4}}\,cm/\sec \] |
| D. | 0.5 amp |
| Answer» C. \[{{10}^{4}}\,cm/\sec \] | |
| 48. |
In a meter bridge, the balancing length from the left end (standard resistance of one ohm is in the right gap) is found to be 20 cm. The value of the unknown resistance is [CBSE PMT 1999; Pb PMT 2004] |
| A. | \[0.8\,\Omega \] |
| B. | \[0.5\,\Omega \] |
| C. | 0.45 amp to the right |
| D. | \[0.25\,\Omega \] |
| Answer» E. | |
| 49. |
A potentiometer consists of a wire of length 4 m and resistance \[10\,\Omega \]. It is connected to a cell of e.m.f. 2 V. The potential difference per unit length of the wire will be [CBSE PMT 1999; AFMC 2001] |
| A. | 0.5 \[V/m\] |
| B. | \[2\,V/m\] |
| C. | \[v\] |
| D. | \[10\,V/m\] |
| Answer» B. \[2\,V/m\] | |
| 50. |
A 100 V voltmeter of internal resistance \[20\,k\Omega \] in series with a high resistance R is connected to a 110 V line. The voltmeter reads 5 V, the value of R is [MP PET 1999] |
| A. | \[210\,k\Omega \] |
| B. | \[315\,k\Omega \] |
| C. | Inside the wire but parallel to it |
| D. | \[440\,k\Omega \] |
| Answer» D. \[440\,k\Omega \] | |