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MCQOPTIONS
This section includes 12583 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.
| 8351. |
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. | 6 W |
| D. | \[\frac{57}{5}\Omega \] |
| Answer» C. 6 W | |
| 8352. |
The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image [IIT-JEE (Screening) 2003] |
| A. | 1.25 cm |
| B. | 2.5 cm |
| C. | 1.05 cm |
| D. | 2 cm |
| Answer» C. 1.05 cm | |
| 8353. |
The contribution in the total current flowing through a semiconductor due to electrons and holes are \[\frac{3}{4}\] and \[\frac{1}{4}\] respectively. If the drift velocity of electrons is \[\frac{5}{2}\] times that of holes at this temperature, then the ratio of concentration of electrons and holes is |
| A. | 6 : 5 |
| B. | 5 : 6 |
| C. | 3 : 2 |
| D. | 2 : 3 |
| Answer» B. 5 : 6 | |
| 8354. |
If the atom \[_{100}F{{m}^{257}}\] follows the Bohr model and the radius of \[_{100}F{{m}^{257}}\] is n times the Bohr radius, then find n [IIT-JEE (Screening) 2003] |
| A. | 100 |
| B. | 200 |
| C. | 4 |
| D. | \[\frac{1}{4}\] |
| Answer» E. | |
| 8355. |
A photon of wavelength 6630 Å is incident on a totally reflecting surface. The momentum delivered by the photon is equal to |
| A. | 6.63 ´ 10?27 kg-m/sec |
| B. | 2 ´ 10?27 kg-m/sec |
| C. | 10?27 kg-m/sec |
| D. | None of these |
| Answer» C. 10?27 kg-m/sec | |
| 8356. |
In a series circuit \[C=2\mu F,\,L=1mH\] and \[R=10\,\Omega ,\]when the current in the circuit is maximum, at that time the ratio of the energies stored in the capacitor and the inductor will be |
| A. | 1 : 1 |
| B. | 1 : 2 |
| C. | 2 : 1 |
| D. | 1 : 5 |
| Answer» E. | |
| 8357. |
Two identical coaxial circular loops carry current i each circulating in the clockwise direction. If the loops are approaching each other, then [MP PMT 1995, 96] |
| A. | Current in each loop increases |
| B. | Current in each loop remains the same |
| C. | Current in each loop decreases |
| D. | Current in one-loop increases and in the other it decreases |
| Answer» D. Current in one-loop increases and in the other it decreases | |
| 8358. |
A dip circle is adjusted so that its needle moves freely in the magnetic meridian. In this position, the angle of dip is 40°. Now the dip circle is rotated so that the plane in which the needle moves makes an angle of 30° with the magnetic meridian. In this position the needle will dip by an angle [DCE 2005] |
| A. | 40° |
| B. | 30° |
| C. | More than 40° |
| D. | Less than 40° |
| Answer» D. Less than 40° | |
| 8359. |
A conducting loop carrying a current I is placed in a uniform magnetic field pointing into the plane of the paper as shown. The loop will have a tendency to [IIT-JEE (Screening) 2003] |
| A. | Contract |
| B. | Expand |
| C. | Move towards +ve x -axis |
| D. | Move towards ?ve x-axis |
| Answer» C. Move towards +ve x -axis | |
| 8360. |
A thermo couple is formed by two metals X and Y metal X comes earlier to Y in Seebeck series. If temperature of hot junction increases beyond the temperature of inversion. Then direction of current in thermocouple will so |
| A. | X to Y through cold junction |
| B. | X to Y through hot junction |
| C. | Y to X through cold junction |
| D. | Both (b) and (c) |
| Answer» E. | |
| 8361. |
Two identical wires have the same fundamental frequency of 400 Hz. when kept under the same tension. If the tension in one wire is increased by 2% the number of beats produced will be [JIPMER 1999] |
| A. | 4 |
| B. | 2 |
| C. | 8 |
| D. | 1 |
| Answer» B. 2 | |
| 8362. |
A 15 g ball is shot from a spring gun whose spring has a force constant of 600 N/m. The spring is compressed by 5 cm. The greatest possible horizontal range of the ball for this compression is (g = 10 m/s2) [DPMT 2004] |
| A. | 6.0 m |
| B. | 10.0 m |
| C. | 12.0 m |
| D. | 8.0 m |
| Answer» C. 12.0 m | |
| 8363. |
A 5cm thick ice block is there on the surface of water in a lake. The temperature of air is ?10°C; how much time it will take to double the thickness of the block (L = 80 cal/g, Kicc = 0.004 Erg/s-k, dice = 0.92 g cm?3) [RPET 1998] |
| A. | 1 hour |
| B. | 191 hours |
| C. | 19.1 hours |
| D. | 1.91 hours |
| Answer» D. 1.91 hours | |
| 8364. |
Find the change in the entropy in the following process 100 gm of ice at 0°C melts when dropped in a bucket of water at 50°C (Assume temperature of water does not change) [BHU (Med.) 2000] |
| A. | ? 4.5 cal/K |
| B. | + 4.5 cal/K |
| C. | +5.4 cal/K |
| D. | ? 5.4 cal/K |
| Answer» C. +5.4 cal/K | |
| 8365. |
10 gm of ice at ? 20°C is dropped into a calorimeter containing 10 gm of water at 10°C; the specific heat of water is twice that of ice. When equilibrium is reached, the calorimeter will contain |
| A. | 20 gm of water |
| B. | 20 gm of ice |
| C. | 10 gm ice and 10 gm water |
| D. | 5 gm ice and 15 gm water |
| Answer» D. 5 gm ice and 15 gm water | |
| 8366. |
A wire of length L and 3 identical cells of negligible internal resistances are connected in series. Due to current, the temperature of the wire is raised by \[\Delta \]T in a time t. A number N of similar cells is now connected in series with a wire of the same material and cross?section but of length 2 L. The temperature of the wire is raised by the same amount \[\Delta \]T in the same time t. the value of N is [IIT-JEE (Screening) 2001] |
| A. | 4 |
| B. | 6 |
| C. | 8 |
| D. | 9 |
| Answer» C. 8 | |
| 8367. |
A potential difference of 2V is applied between the opposite faces of a Ge crystal plate of area 1 cm2 and thickness 0.5 mm. If the concentration of electrons in Ge is 2 ´ 1019/m3 and mobilities of electrons and holes are \[0.36\frac{{{m}^{2}}}{volt-\sec }\] and \[0.14\frac{{{m}^{2}}}{volt-\sec }\] respectively, then the current flowing through the plate will be |
| A. | 0.25 A |
| B. | 0.45 A |
| C. | 0.56 A |
| D. | 0.64 A |
| Answer» E. | |
| 8368. |
The electric potential between a proton and an electron is given by \[V={{V}_{0}}\ln \frac{r}{{{r}_{0}}},\] where \[{{r}_{0}}\] is a constant. Assuming Bohr?s model to be applicable, write variation of \[{{r}_{n}}\] with n, n being the principal quantum number [IIT-JEE (Screening) 2003] |
| A. | \[{{r}_{n}}\propto n\] |
| B. | \[{{r}_{n}}\propto 1/n\] |
| C. | \[{{r}_{n}}\propto {{n}^{2}}\] |
| D. | \[{{r}_{n}}\propto 1/{{n}^{2}}\] |
| Answer» B. \[{{r}_{n}}\propto 1/n\] | |
| 8369. |
Is it possible |
| A. | Yes |
| B. | No |
| C. | Cannot be predicted |
| D. | Insufficient data to reply |
| Answer» B. No | |
| 8370. |
As shown in the figure a metal rod makes contact and complete the circuit. The circuit is perpendicular to the magnetic field with \[B=0.15\,tesla.\] If the resistance is \[3\,\Omega \], force needed to move the rod as indicated with a constant speed of \[2m/sec\] is [MP PET 1994] |
| A. | \[3.75\times {{10}^{-3}}\]N |
| B. | \[3.75\times {{10}^{-2}}\,N\] |
| C. | \[3.75\times {{10}^{2}}\,N\] |
| D. | \[3.75\times {{10}^{-4}}N\] |
| Answer» B. \[3.75\times {{10}^{-2}}\,N\] | |
| 8371. |
A dip needle lies initially in the magnetic meridian when it shows an angle of dip q at a place. The dip circle is rotated through an angle x in the horizontal plane and then it shows an angle of dip \[{\theta }'\]. Then \[\frac{\tan {\theta }'}{\tan \theta }\] is |
| A. | \[\frac{1}{\cos x}\] |
| B. | \[\frac{1}{\sin x}\] |
| C. | \[\frac{1}{\tan x}\] |
| D. | \[\cos x\] |
| Answer» B. \[\frac{1}{\sin x}\] | |
| 8372. |
Wires 1 and 2 carrying currents \[{{i}_{1}}\] and \[{{i}_{2}}\]respectively are inclined at an angle \[\theta \] to each other. What is the force on a small element dl of wire 2 at a distance of r from wire 1 (as shown in figure) due to the magnetic field of wire1 [AIEEE 2002] |
| A. | \[\frac{{{\mu }_{0}}}{2\pi r}{{i}_{1}}\,{{i}_{2}}\,dl\,\tan \theta \] |
| B. | \[\frac{{{\mu }_{0}}}{2\pi r}{{i}_{1}}\,{{i}_{2}}\,dl\,\sin \theta \] |
| C. | \[\frac{{{\mu }_{0}}}{2\pi r}{{i}_{1}}\,{{i}_{2}}\,dl\,\cos \theta \] |
| D. | \[\frac{{{\mu }_{0}}}{4\pi r}{{i}_{1}}\,{{i}_{2}}\,dl\,\sin \theta \] |
| Answer» D. \[\frac{{{\mu }_{0}}}{4\pi r}{{i}_{1}}\,{{i}_{2}}\,dl\,\sin \theta \] | |
| 8373. |
41 forks are so arranged that each produces 5 beats per sec when sounded with its near fork. If the frequency of last fork is double the frequency of first fork, then the frequencies of the first and last fork are respectively [MP PET 1997; KCET 2002] |
| A. | 200, 400 |
| B. | 205, 410 |
| C. | 195, 390 |
| D. | 100, 200 |
| Answer» B. 205, 410 | |
| 8374. |
A particle of mass m is attached to a spring (of spring constant k) and has a natural angular frequency \[{{\omega }_{0}}\]-An external force F (t) proportional to \[\cos \omega \,t((\omega \ne {{\omega }_{0}})\]is applied to the oscillator. The time displacement of the oscillator will be proportional to [AIEEE 2004] |
| A. | \[\frac{m}{\omega _{0}^{2}-{{\omega }^{2}}}\] |
| B. | \[\frac{1}{m(\omega _{0}^{2}-{{\omega }^{2}})}\] |
| C. | \[\frac{1}{m(\omega _{1}^{2}+{{\omega }^{2}})}\] |
| D. | \[\frac{m}{\omega _{1}^{2}+{{\omega }^{2}}}\] |
| Answer» C. \[\frac{1}{m(\omega _{1}^{2}+{{\omega }^{2}})}\] | |
| 8375. |
A one litre glass flask contains some mercury. It is found that at different temperatures the volume of air inside the flak remains the same. What is the volume of mercury in this flask if coefficient of linear expansion of glass is 9 ´ 10?6/°C while of volume expansion of mercury is 1.8 ´ 10?4/°C |
| A. | 50 cc |
| B. | 100 cc |
| C. | 150 cc |
| D. | 200 cc |
| Answer» D. 200 cc | |
| 8376. |
In the given circuit, with steady current, the potential drop across the capacitor must be [IIT-JEE (Screening) 2001] |
| A. | V |
| B. | V / 2 |
| C. | V / 3 |
| D. | 2V / 3 |
| Answer» D. 2V / 3 | |
| 8377. |
There is a uniform electric field of strength \[{{10}^{3}}\,V/m\] along y-axis. A body of mass 1g and charge \[\text{1}{{0}^{\text{6}}}C\] is projected into the field from origin along the positive x-axis with a velocity 10m/s. Its speed in m/s after 10s is (Neglect gravitation) [EAMCET 2001] |
| A. | 10 |
| B. | \[5\sqrt{2}\] |
| C. | \[10\sqrt{2}\] |
| D. | 20 |
| Answer» D. 20 | |
| 8378. |
A monochromatic beam of light falls on YDSE apparatus at some angle (sayq) as shown in figure. A thin sheet of glass is inserted in front of the lower slit S2. The central bright fringe (path difference = 0) will be obtained |
| A. | At O |
| B. | Above O |
| C. | Below O |
| D. | Anywhere depending on angleq, thickness of plate t and refractive index of glass m |
| Answer» E. | |
| 8379. |
The object distance u, the image distance v and the magnification m in a lens follow certain linear relations. These are [Roorkee 2000] |
| A. | \[\frac{1}{u}\text{ versus }\frac{1}{v}\] |
| B. | m versus u |
| C. | u versus v |
| D. | m versus v |
| Answer» B. m versus u | |
| 8380. |
A diode is connected to 220 V (rms) ac in series with a capacitor as shown in figure. The voltage across the capacitor is |
| A. | 220 V |
| B. | 110 V |
| C. | 311.1 V |
| D. | \[\frac{220}{\sqrt{2}}V\] |
| Answer» E. | |
| 8381. |
The wavelengths involved in the spectrum of deuterium \[(_{1}^{2}D)\] are slightly different from that of hydrogen spectrum, because [AIEEE 2003] |
| A. | The attraction between the electr on and the nucleus is different in the two cases |
| B. | The size of the two nuclei are different |
| C. | The nuclear forces are different in the two cases |
| D. | The masses of the two nuclei are different |
| Answer» E. | |
| 8382. |
The ratio of de-Broglie wavelengths of molecules of hydrogen and helium which are at temperature 27oC and 127oC respectively is |
| A. | \[\frac{1}{2}\] |
| B. | \[\sqrt{\frac{3}{8}}\] |
| C. | \[\sqrt{\frac{8}{3}}\] |
| D. | 1 |
| Answer» D. 1 | |
| 8383. |
If \[i={{t}^{2}}\] \[0 |
| A. | \[\frac{{{T}^{2}}}{\sqrt{2}}\] |
| B. | \[\frac{{{T}^{2}}}{2}\] |
| C. | \[\frac{{{T}^{2}}}{\sqrt{5}}\] |
| D. | None of these |
| Answer» D. None of these | |
| 8384. |
A coil of inductance 8.4 mH and resistance 6 W is connected to a 12 V battery. The current in the coil is 1.0 A at approximately the time [IIT-JEE (Screening) 1999; UPSEAT 2003] |
| A. | 500 sec |
| B. | 20 sec |
| C. | 35 milli sec |
| D. | 1 milli sec |
| Answer» E. | |
| 8385. |
A short magnet oscillates with a time period 0.1 s at a place where horizontal magnetic field is \[24\mu T.\] A downward current of 18 A is established in a vertical wire 20 cm east of the magnet. The new time period of oscillator |
| A. | 0.1 s |
| B. | 0.089 s |
| C. | 0.076 s |
| D. | 0.057 s |
| Answer» D. 0.057 s | |
| 8386. |
A and B are two conductors carrying a current i in the same direction. x and y are two electron beams moving in the same direction [Karnataka CET (Engg./Med.) 2002] |
| A. | There will be repulsion between A and B attraction between x and y |
| B. | There will be attraction between A and B, repulsion between x and y |
| C. | There will be repulsion between A and B and also x and y |
| D. | There will be attraction between A and B and also x and y |
| Answer» C. There will be repulsion between A and B and also x and y | |
| 8387. |
An electric bulb rated for 500 watts at 100 volts is used in a circuit having a 200-volt supply. The resistance R that must be put in series with the bulb, so that the bulb draws 500 W is |
| A. | \[10\,\Omega \] |
| B. | \[20\,\Omega \] |
| C. | Rated current through the circuit \[i=\frac{500}{100}=5A\] Potential difference across R, \[100=5\times R\,\Rightarrow \,R=20\,\Omega \] |
| D. | \[50\,\Omega \] |
| Answer» E. | |
| 8388. |
Ten tuning forks are arranged in increasing order of frequency in such a way that any two nearest tuning forks produce 4 beats/sec. The highest frequency is twice of the lowest. Possible highest and the lowest frequencies are [MP PMT 1990; MHCET 2002] |
| A. | 80 and 40 |
| B. | 100 and 50 |
| C. | 44 and 22 |
| D. | 72 and 36 |
| Answer» E. | |
| 8389. |
On a smooth inclined plane, a body of mass M is attached between two springs. The other ends of the springs are fixed to firm supports. If each spring has force constant K, the period of oscillation of the body (assuming the springs as massless) is [NSEP 1994] |
| A. | \[2\pi {{\left( \frac{m}{2K} \right)}^{1/2}}\] |
| B. | \[2\pi {{\left( \frac{2M}{K} \right)}^{1/2}}\] |
| C. | \[2\pi \frac{Mg\sin \theta }{2K}\] |
| D. | \[2\pi {{\left( \frac{2Mg}{K} \right)}^{1/2}}\] |
| Answer» B. \[2\pi {{\left( \frac{2M}{K} \right)}^{1/2}}\] | |
| 8390. |
A solid copper cube of edges \[1\ cm\] is suspended in an evacuated enclosure. Its temperature is found to fall from \[{{100}^{o}}C\] to \[{{99}^{o}}C\] in \[100\ s\]. Another solid copper cube of edges \[2\ cm\], with similar surface nature, is suspended in a similar manner. The time required for this cube to cool from \[{{100}^{o}}C\] to \[{{99}^{o}}C\] will be approximately [MP PMT 1997] |
| A. | \[25\ s\] |
| B. | \[50\ s\] |
| C. | \[200\ s\] |
| D. | \[400\ s\] |
| Answer» D. \[400\ s\] | |
| 8391. |
A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by 62°C, the efficiency of the engine is doubled. The temperatures of the source and sink are [CBSE PMT 2000] |
| A. | 80°C, 37°C |
| B. | 95°C, 28°C |
| C. | 90°C, 37°C |
| D. | 99°C, 37°C |
| Answer» E. | |
| 8392. |
In the given circuit, it is observed that the current I is independent of the value of the resistance R6. Then the resistance values must satisfy [IIT-JEE (Screening) 2001] |
| A. | \[{{R}_{1}}{{R}_{2}}{{R}_{5}}={{R}_{3}}{{R}_{4}}{{R}_{6}}\] |
| B. | \[\frac{1}{{{R}_{5}}}+\frac{1}{{{R}_{6}}}\]\[=\frac{1}{{{R}_{1}}+{{R}_{2}}}+\frac{1}{{{R}_{3}}+{{R}_{4}}}\] |
| C. | \[{{R}_{1}}{{R}_{4}}={{R}_{2}}{{R}_{3}}\] |
| D. | \[{{R}_{1}}{{R}_{3}}={{R}_{2}}{{R}_{4}}={{R}_{5}}{{R}_{6}}\] |
| Answer» D. \[{{R}_{1}}{{R}_{3}}={{R}_{2}}{{R}_{4}}={{R}_{5}}{{R}_{6}}\] | |
| 8393. |
A uniform electric field pointing in positive x-direction exists in a region. Let A be the origin, B be the point on the x-axis at \[x=+1\]cm and C be the point on the y-axis at \[y=+1\]cm. Then the potentials at the points A, B and C satisfy [IIT-JEE (Screening) 2001] |
| A. | \[{{V}_{A}}<{{V}_{B}}\] |
| B. | \[{{V}_{A}}>{{V}_{B}}\] |
| C. | \[{{V}_{A}}<{{V}_{C}}\] |
| D. | \[{{V}_{A}}>{{V}_{C}}\] |
| Answer» C. \[{{V}_{A}}<{{V}_{C}}\] | |
| 8394. |
The maximum intensity in Young's double slit experiment is I0. Distance between the slits is d = 5l, where l is the wavelength of monochromatic light used in the experiment. What will be the intensity of light in front of one of the slits on a screen at a distance \[D=10\,d\] |
| A. | \[\frac{{{I}_{0}}}{2}\] |
| B. | \[\frac{3}{4}{{I}_{0}}\] |
| C. | I0 |
| D. | \[\frac{{{I}_{0}}}{4}\] |
| Answer» B. \[\frac{3}{4}{{I}_{0}}\] | |
| 8395. |
A hollow double concave lens is made of very thin transparent material. It can be filled with air or either of two liquids L1 and L2 having refractive indices n1 and n2 respectively (n2>n1>1). The lens will diverge a parallel beam of light if it is filled with [IIT-JEE (Screening) 2000] |
| A. | Air and placed in air |
| B. | Air and immersed in L1 |
| C. | L1 and immersed in L2 |
| D. | L2 and immersed in L1 |
| Answer» E. | |
| 8396. |
Find VAB [RPMT 2000] |
| A. | 10 V |
| B. | 20 V |
| C. | 30 V |
| D. | None of these |
| Answer» B. 20 V | |
| 8397. |
Which of the following atoms has the lowest ionization potential [AIEEE 2003] |
| A. | \[_{8}^{16}O\] |
| B. | \[_{7}^{14}N\] |
| C. | \[_{55}^{133}Cs\] |
| D. | \[_{18}^{40}Ar\] |
| Answer» D. \[_{18}^{40}Ar\] | |
| 8398. |
The X-ray wavelength of \[{{L}_{\alpha }}\] line of platinum (Z=78) is \[1.30{AA}.\] The X ?ray wavelength of \[{{L}_{\alpha }}\] line of Molybdenum (Z=42) is [EAMCET (Eng.) 2000] |
| A. | 5.41 \[\overset{\text{o}}{\mathop{\text{A}}}\,\] |
| B. | 4.20 \[\overset{\text{o}}{\mathop{\text{A}}}\,\] |
| C. | 2.70 \[\overset{\text{o}}{\mathop{\text{A}}}\,\] |
| D. | 1.35 \[\overset{\text{o}}{\mathop{\text{A}}}\,\] |
| Answer» B. 4.20 \[\overset{\text{o}}{\mathop{\text{A}}}\,\] | |
| 8399. |
A physicist works in a laboratory where the magnetic field is 2 T. She wears a necklace enclosing area 0.01 m2 in such a way that the plane of the necklace is normal to the field and is having a resistance R = 0.01 W. Because of power failure, the field decays to 1 T in time 10?3 seconds. Then what is the total heat produced in her necklace ? (T = Tesla) [Orissa JEE 2002] |
| A. | 10 J |
| B. | 20 J |
| C. | 30 J |
| D. | 40 J |
| Answer» B. 20 J | |
| 8400. |
An elastic circular wire of length l carries a current I. It is placed in a uniform magnetic field \[\overset{\to }{\mathop{B}}\,\] (Out of paper) such that its plane is perpendicular to the direction of \[\overset{\to }{\mathop{B}}\,\]. The wire will experience [MP PET 2000] |
| A. | No force |
| B. | A stretching force |
| C. | A compressive force |
| D. | A torque |
| Answer» C. A compressive force | |