MCQOPTIONS
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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.
| 8401. |
The thermo e.m.f. of a thermo-couple is \[25\mu V{{/}^{o}}C\] at room temperature. A galvanometer of 40 ohm resistance, capable of detecting current as low as \[{{10}^{-5}}A,\] is connected with the thermocouple. The smallest temperature difference that can be detected by this system is [AIEEE 2003] |
| A. | \[{{20}^{o}}C\] |
| B. | \[{{16}^{o}}C\] |
| C. | \[{{12}^{o}}C\] |
| D. | \[{{8}^{o}}C\] |
| Answer» C. \[{{12}^{o}}C\] | |
| 8402. |
Consider ten identical sources of sound all giving the same frequency but having phase angles which are random. If the average intensity of each source is \[{{I}_{0}}\], the average of resultant intensity I due to all these ten sources will be [MP PMT 1990] |
| A. | \[I=100\,{{I}_{0}}\] |
| B. | \[I=10\,{{I}_{0}}\] |
| C. | \[I={{I}_{0}}\] |
| D. | \[I=\sqrt{10}\,{{I}_{0}}\] |
| Answer» C. \[I={{I}_{0}}\] | |
| 8403. |
One end of a long metallic wire of length L is tied to the ceiling. The other end is tied to massless spring of spring constant K. A mass m hangs freely from the free end of the spring. The area of cross-section and Young's modulus of the wire are A and Y respectively. If the mass is slightly pulled down and released, it will oscillate with a time period T equal to [IIT 1993] |
| A. | \[2\pi \left( \frac{m}{K} \right)\] |
| B. | \[2\pi {{\left\{ \frac{(YA+KL)m}{YAK} \right\}}^{1/2}}\] |
| C. | \[2\pi \frac{mYA}{KL}\] |
| D. | \[2\pi \frac{mL}{YA}\] |
| Answer» C. \[2\pi \frac{mYA}{KL}\] | |
| 8404. |
A solid sphere and a hollow sphere of the same material and size are heated to the same temperature and allowed to cool in the same surroundings. If the temperature difference between each sphere and its surroundings is \[T\], then [Manipal MEE 1995] |
| A. | The hollow sphere will cool at a faster rate for all values of \[T\] |
| B. | The solid sphere will cool at a faster rate for all values of \[T\] |
| C. | Both spheres will cool at the same rate for all values of \[T\] |
| D. | Both spheres will cool at the same rate only for small values of \[T\] |
| Answer» B. The solid sphere will cool at a faster rate for all values of \[T\] | |
| 8405. |
A thermally insulated rigid container contains an ideal gas heated by a filament of resistance 100 W through a current of 1A for 5 min then change in internal energy is [IIT-JEE (Screening) 2005] |
| A. | 0 kJ |
| B. | 10 kJ |
| C. | 20 kJ |
| D. | 30 kJ |
| Answer» E. | |
| 8406. |
The coefficient of linear expansion of crystal in one direction is \[{{\alpha }_{1}}\] and that in every direction perpendicular to it is \[{{\alpha }_{2}}\]. The coefficient of cubical expansion is |
| A. | \[{{\alpha }_{1}}+{{\alpha }_{2}}\] |
| B. | \[2{{\alpha }_{1}}+{{\alpha }_{2}}\] |
| C. | \[{{\alpha }_{1}}+2{{\alpha }_{2}}\] |
| D. | None of these |
| Answer» D. None of these | |
| 8407. |
A wire of resistance 10 W is bent to form a circle. P and Q are points on the circumference of the circle dividing it into a quadrant and are connected to a Battery of 3 V and internal resistance 1 W as shown in the figure. The currents in the two parts of the circle are [Roorkee 1999] |
| A. | \[\frac{6}{23}A\,\,\text{and}\,\text{ }\frac{18}{23}A\] |
| B. | \[\frac{5}{26}A\,\,\text{and}\,\frac{15}{26}A\] |
| C. | \[\frac{4}{25}A\,\,\text{and}\,\text{ }\frac{12}{25}A\] |
| D. | \[\frac{3}{25}A\,\,\text{and}\,\text{ }\frac{9}{25}A\] |
| Answer» B. \[\frac{5}{26}A\,\,\text{and}\,\frac{15}{26}A\] | |
| 8408. |
Three positive charges of equal value q are placed at the vertices of an equilateral triangle. The resulting lines of force should be sketched as in [IIT-JEE (Screening) 2001] |
| A. | |
| B. | |
| C. | |
| D. | |
| Answer» D. | |
| 8409. |
. Shown in the figure here is a convergent lens placed inside a cell filled with a liquid. The lens has focal length + 20 cm when in air and its material has refractive index 1.50. If the liquid has refractive index 1.60, the focal length of the system is [NSEP 1994; DPMT 2000] |
| A. | + 80 cm |
| B. | ? 80 cm |
| C. | ? 24 cm |
| D. | ?100 cm |
| Answer» E. | |
| 8410. |
The circuit shown in following figure contains two diode D1 and D2 each with a forward resistance of 50 ohms and with infinite backward resistance. If the battery voltage is 6 V, the current through the 100 ohm resistance (in amperes) is [IIT-JEE 1997] |
| A. | Zero |
| B. | 0.02 |
| C. | 0.03 |
| D. | 0.036 |
| Answer» C. 0.03 | |
| 8411. |
A Hydrogen atom and a \[L{{i}^{++}}\] ion are both in the second excited state. If \[{{l}_{H}}\] and \[{{l}_{Li}}\] are their respective electronic angular momenta, and \[{{E}_{H}}\] and \[{{E}_{Li}}\] their respective energies, then [IIT-JEE (Screening) 2002] |
| A. | \[{{l}_{H}}>{{l}_{Li}}\,\text{ and }|{{E}_{H}}|>|{{E}_{Li}}|\] |
| B. | \[{{l}_{H}}={{l}_{Li}}\text{ and }|{{E}_{H}}|<|{{E}_{Li}}|\] |
| C. | \[{{l}_{H}}={{l}_{Li}}\text{ and }|{{E}_{H}}|>|{{E}_{Li}}|\] |
| D. | \[{{l}_{H}}<{{l}_{Li}}\text{ and }|{{E}_{H}}|<|{{E}_{Li}}|\] |
| Answer» C. \[{{l}_{H}}={{l}_{Li}}\text{ and }|{{E}_{H}}|>|{{E}_{Li}}|\] | |
| 8412. |
Electrons with energy 80 keV are incident on the tungsten target of an X-ray tube. K shell electrons of tungsten have ionization energy 72.5 keV. X-rays emitted by the tube contain only [IIT-JEE (Screening) 2000] |
| A. | A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of ~ 0.155Å |
| B. | A continuous X-ray spectrum (Bremsstrahlung] with all wavelengths |
| C. | The characteristic X-rays spectrum of tungsten |
| D. | A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of ~ 0.155Å and the characteristic X-ray spectrum of tungsten |
| Answer» E. | |
| 8413. |
In the adjoining ac circuit the voltmeter whose reading will be zero at resonance is |
| A. | V1 |
| B. | V2 |
| C. | V3 |
| D. | V4 |
| Answer» E. | |
| 8414. |
A short-circuited coil is placed in a time-varying magnetic field. Electrical power is dissipated due to the current induced in the coil. If the number of turns were to be quadrupled and the wire radius halved, the electrical power dissipated would be [IIT-JEE (Screening) 2002] |
| A. | Halved |
| B. | The same |
| C. | Doubled |
| D. | Quadrupled |
| Answer» C. Doubled | |
| 8415. |
A dip needle vibrates in the vertical plane perpendicular to the magnetic meridian. The time period of vibration is found to be 2 seconds. The same needle is then allowed to vibrate in the horizontal plane and the time period is again found to be 2 seconds. Then the angle of dip is |
| A. | 0o |
| B. | 30o |
| C. | 45o |
| D. | 90o |
| Answer» D. 90o | |
| 8416. |
A particle of charge q and mass m moves in a circular orbit of radius r with angular speed \[\omega \]. The ratio of the magnitude of its magnetic moment to that of its angular momentum depends on [IIT-JEE (Screening) 2000] |
| A. | \[\omega \,\text{and}\,q\] |
| B. | \[\omega \,\,q\,\text{and}\,m\] |
| C. | \[q\,\,\text{and}\,m\] |
| D. | \[\omega \,\text{and}\,m\] |
| Answer» D. \[\omega \,\text{and}\,m\] | |
| 8417. |
The temperature of the cold junction of a thermocouple is \[{{0}^{o}}C\] and temperature of the hot junction is \[{{T}^{o}}C.\] The thermo e.m.f. is given by the relation \[E=AT-\frac{1}{2}B{{T}^{2}}\] (where A = 16 and B = 0.08). The temperature of inversion is [AIIMS 2001] |
| A. | \[{{100}^{o}}C\] |
| B. | \[{{300}^{o}}C\] |
| C. | \[{{400}^{o}}C\] |
| D. | \[{{500}^{o}}C\] |
| Answer» D. \[{{500}^{o}}C\] | |
| 8418. |
The total energy radiated from a black body source is collected for one minute and is used to heat a quantity of water. The temperature of water is found to increase form \[{{20}^{o}}C\] to \[{{20.5}^{o}}C\]. If the absolute temperature of the black body is doubled and the experiment is repeated with the same quantity of water at \[{{20}^{o}}C\], the temperature of water will be [UPSEAT 2004] |
| A. | \[{{21}^{o}}C\] |
| B. | \[{{22}^{o}}C\] |
| C. | \[{{24}^{o}}C\] |
| D. | \[{{28}^{o}}C\] |
| Answer» E. | |
| 8419. |
Initial pressure and volume of a gas are P and V respectively. First it is expanded isothermally to volume 4V and then compressed adiabatically to volume V. The final pressure of gas will be [CBSE PMT 1999] |
| A. | 1P |
| B. | 2P |
| C. | 4P |
| D. | 8P |
| Answer» C. 4P | |
| 8420. |
In a vertical U-tube containing a liquid, the two arms are maintained at different temperatures \[{{t}_{1}}\] and \[{{t}_{2}}\]. The liquid columns in the two arms have heights \[{{l}_{1}}\] and \[{{l}_{2}}\] respectively. The coefficient of volume expansion of the liquid is equal to |
| A. | \[\frac{{{l}_{1}}-{{l}_{2}}}{{{l}_{2}}{{t}_{1}}-{{l}_{1}}{{t}_{2}}}\] |
| B. | \[\frac{{{l}_{1}}-{{l}_{2}}}{{{l}_{1}}{{t}_{1}}-{{l}_{2}}{{t}_{2}}}\] |
| C. | \[\frac{{{l}_{1}}+{{l}_{2}}}{{{l}_{2}}{{t}_{1}}+{{l}_{1}}{{t}_{2}}}\] |
| D. | \[\frac{{{l}_{1}}+{{l}_{2}}}{{{l}_{1}}{{t}_{1}}+{{l}_{2}}{{t}_{2}}}\] |
| Answer» B. \[\frac{{{l}_{1}}-{{l}_{2}}}{{{l}_{1}}{{t}_{1}}-{{l}_{2}}{{t}_{2}}}\] | |
| 8421. |
A set of n identical cubical blocks lies at rest parallel to each other along a line on a smooth horizontal surface. The separation between the near surfaces of any two adjacent blocks is L. The block at one end is given a speed v towards the next one at time \[t=0\]. All collisions are completely inelastic, then [IIT 1995] |
| A. | The last block starts moving at \[t=\frac{(n-1)L}{v}\] |
| B. | The last block starts moving at \[t=\frac{n(n-1)L}{2v}\] |
| C. | The centre of mass of the system will have a final speed v |
| D. | The centre of mass of the system will have a final speed \[\frac{v}{n}\] |
| Answer» C. The centre of mass of the system will have a final speed v | |
| 8422. |
Four light waves are represented by (i) y = a1 sinw t (ii) \[y={{a}_{2}}\sin (\omega \,t+\varphi )\] (iii) \[y={{a}_{1}}\sin 2\omega \,t\] (iv) \[y={{a}_{2}}\sin 2(\,\omega \,t+\varphi )\] Interference fringes may be observed due to superposition of |
| A. | (i) and (ii) |
| B. | (i) and (iii) |
| C. | (ii) and (iv) |
| D. | (iii) and (iv) |
| Answer» E. | |
| 8423. |
A luminous object is placed at a distance of 30 cm from the convex lens of focal length 20 cm. On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature 10 cm be placed in order to have an upright image of the object coincident with it [CBSE PMT 1998; JIPMER 2001, 02] |
| A. | 12 cm |
| B. | 30 cm |
| C. | 50 cm |
| D. | 60 cm |
| Answer» D. 60 cm | |
| 8424. |
In the following circuits PN-junction diodes D1, D2 and D3 are ideal for the following potential of A and B, the correct increasing order of resistance between A and B will be (i) ? 10 V, ? 5V (ii) ? 5V, ? 10 V (iii) ? 4V, ? 12V |
| A. | (i) < (ii) < (iii) |
| B. | (iii) < (ii) < (i) |
| C. | (ii) = (iii) < (i) |
| D. | (i) = (iii) < (ii) |
| Answer» D. (i) = (iii) < (ii) | |
| 8425. |
In the Bohr model of the hydrogen atom, let R, v and E represent the radius of the orbit, the speed of electron and the total energy of the electron respectively. Which of the following quantity is proportional to the quantum number n [Pb. PET 2001; KCET 2002] |
| A. | R/E |
| B. | E/v |
| C. | RE |
| D. | vR |
| Answer» E. | |
| 8426. |
The \[{{K}_{\alpha }}\]X-ray emission line of tungsten occurs at \[\lambda =0.021\]\[nm\]. The energy difference between K and L levels in this atom is about [IIT 1997 Cancelled] |
| A. | 0.51MeV |
| B. | 1.2 MeV |
| C. | 59 KeV |
| D. | 13.6 eV |
| Answer» D. 13.6 eV | |
| 8427. |
For a series RLC circuit R = XL = 2XC. The impedance of the circuit and phase difference (between) V and i will be |
| A. | \[\frac{\sqrt{5}R}{2},\,{{\tan }^{-1}}(2)\] |
| B. | \[\frac{\sqrt{5}R}{2},{{\tan }^{-1}}\left( \frac{1}{2} \right)\] |
| C. | \[\sqrt{5}{{X}_{C}},{{\tan }^{-1}}(2)\] |
| D. | \[\sqrt{5}R,\,{{\tan }^{-1}}\left( \frac{1}{2} \right)\] |
| Answer» C. \[\sqrt{5}{{X}_{C}},{{\tan }^{-1}}(2)\] | |
| 8428. |
As shown in the figure, P and Q are two coaxial conducting loops separated by some distance. When the switch S is closed, a clockwise current \[{{I}_{P}}\] flows in P (as seen by E) and an induced current \[{{I}_{{{Q}_{1}}}}\] flows in Q. The switch remains closed for a long time. When S is opened, a current \[{{I}_{{{Q}_{2}}}}\] flows in Q. Then the directions of \[{{I}_{{{Q}_{1}}}}\] and \[{{I}_{{{Q}_{2}}}}\] (as seen by E) are [IIT JEE (Screening) 2002] |
| A. | Respectively clockwise and anticlockwise |
| B. | Both clockwise |
| C. | Both anticlockwise |
| D. | Respectively anticlockwise and clockwise |
| Answer» E. | |
| 8429. |
A magnet is suspended in the magnetic meridian with an untwisted wire. The upper end of wire is rotated through 180o to deflect the magnet by 30o from magnetic meridian. When this magnet is replaced by another magnet, the upper end of wire is rotated through 270o to deflect the magnet 30o from magnetic meridian. The ratio of magnetic moments of magnets is |
| A. | 1 : 5 |
| B. | 1 : 8 |
| C. | 5 : 8 |
| D. | 8 : 5 |
| Answer» D. 8 : 5 | |
| 8430. |
A thin circular wire carrying a current I has a magnetic moment M. The shape of the wire is changed to a square and it carries the same current. It will have a magnetic moment [MP PET 2003; MP PMT 2004] |
| A. | M |
| B. | \[\frac{4}{{{\pi }^{2}}}M\] |
| C. | \[\frac{4}{\pi }M\] |
| D. | \[\frac{\pi }{4}M\] |
| Answer» E. | |
| 8431. |
The temperature of the cold junction of thermo‑couple is \[0{}^\circ C\] and the temperature of hot junction is \[T{}^\circ C\]. The e.m.f. is \[E=16T-0.04{{T}^{2}}\mu \] volts. The temperature of inversion is [EAMCET 1994] |
| A. | \[200{}^\circ C\] |
| B. | \[400{}^\circ C\] |
| C. | \[100{}^\circ C\] |
| D. | \[300{}^\circ C\] |
| Answer» C. \[100{}^\circ C\] | |
| 8432. |
The equation \[y=A{{\cos }^{2}}\left( 2\pi \ nt-2\pi \frac{x}{\lambda } \right)\] represents a wave with [KCET 2002] |
| A. | Amplitude A/2, frequency \[2n\] and wavelength \[\lambda /2\] |
| B. | Amplitude A/2, frequency \[2n\] and wavelength \[\lambda \] |
| C. | Amplitude A, frequency \[2n\] and wavelength \[2\lambda \] |
| D. | Amplitude A, frequency \[n\] and wavelength \[\lambda \] |
| Answer» B. Amplitude A/2, frequency \[2n\] and wavelength \[\lambda \] | |
| 8433. |
Three discs A, B and C having radii 2m, 4m, and 6m respectively are coated with carbon black on their other surfaces. The wavelengths corresponding to maximum intensity are 300 nm, 400 nm and 500 nm, respectively. The power radiated by them are Qa, Qb, and Qc respectively [IIT-JEE (Screening) 2004] |
| A. | Qa is maximum |
| B. | Qb is maximum |
| C. | Qc is maximum |
| D. | Qa = Qb = Qc |
| Answer» C. Qc is maximum | |
| 8434. |
In an industrial process 10 kg of water per hour is to be heated from 20°C to 80°C. To do this steam at 150°C is passed from a boiler into a copper coil immersed in water. The steam condenses in the coil and is returned to the boiler as water at 90°C. how many kg of steam is required per hour. (Specific heat of steam = 1 calorie per gm°C, Latent heat of vaporisation = 540 cal/gm) |
| A. | 1 gm |
| B. | 1 kg |
| C. | 10 gm |
| D. | 10 kg |
| Answer» C. 10 gm | |
| 8435. |
Two resistances \[{{R}_{1}}\] and \[{{R}_{2}}\] are made of different materials. The temperature coefficient of the material of \[{{R}_{1}}\] is \[\alpha \] and of the material of \[{{R}_{2}}\] is \[-\beta \]. The resistance of the series combination of \[{{R}_{1}}\] and \[{{R}_{2}}\] will not change with temperature, if \[{{R}_{1}}/{{R}_{2}}\] equals [MP PMT 1997] |
| A. | \[\frac{\alpha }{\beta }\] |
| B. | \[\frac{\alpha +\beta }{\alpha -\beta }\] |
| C. | \[\frac{{{\alpha }^{2}}+{{\beta }^{2}}}{\alpha \beta }\] |
| D. | \[\frac{\beta }{\alpha }\] |
| Answer» E. | |
| 8436. |
To break a wire, a force of \[{{10}^{6}}\,N/{{m}^{2}}\] is required. If the density of the material is \[3\times {{10}^{3}}\,kg/{{m}^{3}}\], then the length of the wire which will break by its own weight will be [Roorkee 1979; DPMT 2004] |
| A. | 34 m |
| B. | 30 m |
| C. | 300 m |
| D. | 3 m |
| Answer» B. 30 m | |
| 8437. |
The magnitudes of the gravitational force at distances \[{{r}_{1}}\] and \[{{r}_{2}}\] from the centre of a uniform sphere of radius R and mass M are \[{{F}_{1}}\] and \[{{F}_{2}}\] respectively. Then [IIT 1994] |
| A. | \[\frac{{{F}_{1}}}{{{F}_{2}}}=\frac{{{r}_{1}}}{{{r}_{2}}}\] if \[{{r}_{1}}<R\] and \[{{r}_{2}}<R\] |
| B. | \[\frac{{{F}_{1}}}{{{F}_{2}}}=\frac{r_{1}^{2}}{r_{2}^{2}}\] if \[{{r}_{1}}>R\] and \[{{r}_{2}}>R\] |
| C. | \[\frac{{{F}_{1}}}{{{F}_{2}}}=\frac{{{r}_{1}}}{{{r}_{2}}}\] if \[{{r}_{1}}>R\] and \[{{r}_{2}}>R\] |
| D. | \[\frac{{{F}_{1}}}{{{F}_{2}}}=\frac{r_{2}^{2}}{r_{1}^{2}}\] if \[{{r}_{1}}<R\] and \[{{r}_{2}}<R\] |
| Answer» B. \[\frac{{{F}_{1}}}{{{F}_{2}}}=\frac{r_{1}^{2}}{r_{2}^{2}}\] if \[{{r}_{1}}>R\] and \[{{r}_{2}}>R\] | |
| 8438. |
A uniform chain of length L and mass M is lying on a smooth table and one third of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, the work required to pull the hanging part on to the table is [IIT 1985; MNR 1990; AIEEE 2002; MP PMT 1994, 97, 2000; JIPMER 2000] |
| A. | \[MgL\] |
| B. | \[MgL/3\] |
| C. | \[MgL/9\] |
| D. | \[MgL/18\] |
| Answer» E. | |
| 8439. |
If \[L,\,C\] and \[R\] represent inductance, capacitance and resistance respectively, then which of the following does not represent dimensions of frequency [IIT 1984] |
| A. | \[\frac{1}{RC}\] |
| B. | \[\frac{R}{L}\] |
| C. | \[\frac{1}{\sqrt{LC}}\] |
| D. | \[\frac{C}{L}\] |
| Answer» E. | |
| 8440. |
In the adjacent diagram, CP represents a wavefront and AO & BP, the corresponding two rays. Find the condition on q for constructive interference at P between the ray BP and reflected ray OP [IIT-JEE (Screening) 2003] |
| A. | cosq = 3l/2d |
| B. | cosq = l/4d |
| C. | secq ? cosq = l/d |
| D. | secq ? cosq = 4l/d |
| Answer» C. secq ? cosq = l/d | |
| 8441. |
A concave mirror of focal length \[100cm\] is used to obtain the image of the sun which subtends an angle of \[30{}^\circ .\] The diameter of the image of the sun will be |
| A. | \[1.74cm\] |
| B. | \[0.87cm\] |
| C. | \[0.435cm\] |
| D. | \[100cm\] |
| Answer» C. \[0.435cm\] | |
| 8442. |
The probability of electrons to be found in the conduction band of an intrinsic semiconductor at a finite temperature [IIT-JEE 1995; DPMT 2004] |
| A. | Decreases exponentially with increasing band gap |
| B. | Increases exponentially with increasing band gap |
| C. | Decreases with increasing temperature |
| D. | Is independent of the temperature and the band gap |
| Answer» B. Increases exponentially with increasing band gap | |
| 8443. |
In a diode AM-detector, the output circuit consist of R = 1kW and C = 10 pF. A carrier signal of 100 kHz is to be detected. Is it good |
| A. | Yes |
| B. | No |
| C. | Information is not sufficient |
| D. | None of these |
| Answer» C. Information is not sufficient | |
| 8444. |
The ratio of the speed of the electrons in the ground state of hydrogen to the speed of light in vacuum is [MNR 1994; MP PMT 1994] |
| A. | 1/2 |
| B. | 2/137 |
| C. | 1/137 |
| D. | 1/237 |
| Answer» D. 1/237 | |
| 8445. |
A particle of mass M at rest decays into two particles of masses m1 and m2, having non-zero velocities. The ratio of the de-Broglie wavelengths of the particles, \[{{\lambda }_{1}}/{{\lambda }_{2}}\]is [IIT-JEE 1999; KCET 2003] |
| A. | \[{{m}_{1}}/{{m}_{2}}\] |
| B. | \[{{m}_{2}}/{{m}_{1}}\] |
| C. | 1.0 |
| D. | \[\sqrt{{{m}_{2}}}/\sqrt{{{m}_{1}}}\] |
| Answer» D. \[\sqrt{{{m}_{2}}}/\sqrt{{{m}_{1}}}\] | |
| 8446. |
In an LR-circuit, the inductive reactance is equal to the resistance R of the circuit. An e.m.f. \[E={{E}_{0}}\cos (\omega t)\] applied to the circuit. The power consumed in the circuit is [MP PMT 1997] |
| A. | \[\frac{E_{0}^{2}}{R}\] |
| B. | \[\frac{E_{0}^{2}}{2R}\] |
| C. | \[\frac{E_{0}^{2}}{4R}\] |
| D. | \[\frac{E_{0}^{2}}{8R}\] |
| Answer» D. \[\frac{E_{0}^{2}}{8R}\] | |
| 8447. |
Two short magnets placed along the same axis with their like poles facing each other repel each other with a force which varies inversely as |
| A. | Square of the distance |
| B. | Cube of the distance |
| C. | Distance |
| D. | Fourth power of the distance |
| Answer» E. | |
| 8448. |
The field normal to the plane of a wire of n turns and radius r which carries a current i is measured on the axis of the coil at a small distance h from the centre of the coil. This is smaller than the field at the centre by the fraction |
| A. | \[\frac{3}{2}\frac{{{h}^{2}}}{{{r}^{2}}}\] |
| B. | \[\frac{2}{3}\frac{{{h}^{2}}}{{{r}^{2}}}\] |
| C. | \[\frac{3}{2}\frac{{{r}^{2}}}{{{h}^{2}}}\] |
| D. | \[\frac{2}{3}\frac{{{r}^{2}}}{{{h}^{2}}}\] |
| Answer» B. \[\frac{2}{3}\frac{{{h}^{2}}}{{{r}^{2}}}\] | |
| 8449. |
An immersion heater is rated 836 watt. It should heat 1 litre of water from \[10{}^\circ C\] to \[40{}^\circ C\] in about [AIEEE 2004] |
| A. | 200 sec |
| B. | 150 sec |
| C. | 836 sec |
| D. | 418 sec |
| Answer» C. 836 sec | |
| 8450. |
The ends of a stretched wire of length L are fixed at \[x=0\] and \[x=L.\] In one experiment, the displacement of the wire is \[{{y}_{1}}=A\sin (\pi x/L)\sin \omega t\] and energy is \[{{E}_{1}}\], and in another experiment its displacement is \[{{y}_{2}}=A\sin (2\pi x/L)\sin 2\omega t\] and energy is \[{{E}_{2}}\]. Then [IIT-JEE (Screening) 2001] |
| A. | \[{{E}_{2}}={{E}_{1}}\] |
| B. | \[{{E}_{2}}=2{{E}_{1}}\] |
| C. | \[{{E}_{2}}=4{{E}_{1}}\] |
| D. | \[{{E}_{2}}=16{{E}_{1}}\] |
| Answer» D. \[{{E}_{2}}=16{{E}_{1}}\] | |