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.
| 3401. |
A convex lens has 9 cm focal length and a concave lens has -18 cm focal length. The focal length of the combination in contact will be [RPMT 1999] |
| A. | 9 cm |
| B. | - 18 cm |
| C. | - 9 cm |
| D. | 18 cm |
| Answer» E. | |
| 3402. |
A lens which has focal length of 4 cm and refractive index of 1.4 is immersed in a liquid of refractive index 1.6, then the focal length will be [RPMT 1999] |
| A. | - 12.8 cm |
| B. | 32 cm |
| C. | 12.8 cm |
| D. | - 32 cm |
| Answer» B. 32 cm | |
| 3403. |
A lens of focal power 0.5 D is [JIPMER 1999] |
| A. | A convex lens of focal length 0.5 m |
| B. | A concave lens of focal length 0.5 m |
| C. | A convex lens of focal length 2 m |
| D. | A concave lens of focal length 2 m |
| Answer» D. A concave lens of focal length 2 m | |
| 3404. |
A double convex lens of glass of m = 1.5 has radius of curvature of each of its surface is 0.2 m. The power of the lens is [JIPMER 1999] |
| A. | + 10 dioptres |
| B. | - 10 dioptres |
| C. | - 5 dioptres |
| D. | +5 dioptres |
| Answer» E. | |
| 3405. |
A convex lens of power + 6D is placed in contact with a concave lens of power ? 4D. What is the nature and focal length of the combination [AMU (Engg.) 1999] |
| A. | Concave, 25 cm |
| B. | Convex, 50 cm |
| C. | Concave, 20 cm |
| D. | Convex, 100 cm |
| Answer» C. Concave, 20 cm | |
| 3406. |
A convex lens is used to form real image of an object on a screen. It is observed that even when the positions of the object and that screen are fixed there are two positions of the lens to form real images. If the heights of the images are 4 cm and 9 cm respectively, the height of the object is [AMU (Med.) 1999] |
| A. | 2.25 cm |
| B. | 6.00 cm |
| C. | 6.50 cm |
| D. | 36.00 cm |
| Answer» C. 6.50 cm | |
| 3407. |
A concave lens of focal length 20 cm placed in contact with a plane mirror acts as a [SCRA 1998] |
| A. | Convex mirror of focal length 10 cm |
| B. | Concave mirror of focal length 40 cm |
| C. | Concave mirror of focal length 60 cm |
| D. | Concave mirror of focal length 10 cm |
| Answer» B. Concave mirror of focal length 40 cm | |
| 3408. |
A substance is behaving as convex lens in air and concave in water, then its refractive index is [BHU 1998] |
| A. | Smaller than air |
| B. | Greater than both air and water |
| C. | Greater than air but less than water |
| D. | Almost equal to water |
| Answer» D. Almost equal to water | |
| 3409. |
Two thin lenses whose powers are +2D and -4D respectively combine, then the power of combination is [AFMC 1998; CPMT 1996; Very Similar to BHU 2004] |
| A. | - 2D |
| B. | + 2D |
| C. | - 4D |
| D. | + 4D |
| Answer» B. + 2D | |
| 3410. |
A convex lens of focal length \[f\] produces an image \[\frac{1}{n}\] times than that of the size of the object. The distance of the object from the lens is [BHU 1997; JIPMER 2001, 02] |
| A. | \[nf\] |
| B. | \[\frac{f}{n}\] |
| C. | \[(n+1)\,f\] |
| D. | \[(n-1)\,f\] |
| Answer» D. \[(n-1)\,f\] | |
| 3411. |
\[{{f}_{v}}\]and \[{{f}_{r}}\] are the focal lengths of a convex lens for violet and red light respectively and \[{{F}_{v}}\] and \[{{F}_{r}}\]are the focal lengths of a concave lens for violet and red light respectively, then [CBSE PMT 1996] |
| A. | \[{{f}_{v}}<{{f}_{r}}\] and \[{{F}_{v}}>{{F}_{r}}\] |
| B. | \[{{f}_{v}}<{{f}_{R}}\] and \[{{F}_{v}}<{{F}_{r}}\] |
| C. | \[{{f}_{c}}>{{f}_{r}}\] and \[{{F}_{v}}>{{F}_{r}}\] |
| D. | \[{{f}_{v}}>{{f}_{r}}\] and \[{{F}_{v}}<{{F}_{r}}\] |
| Answer» C. \[{{f}_{c}}>{{f}_{r}}\] and \[{{F}_{v}}>{{F}_{r}}\] | |
| 3412. |
If a convex lens of focal length 80 cm and a concave lens of focal length 50 cm are combined together, what will be their resulting power [CBSE PMT 1996; AFMC 2002] |
| A. | + 6.5D |
| B. | - 6.5 D |
| C. | + 7.5 D |
| D. | - 0.75 D |
| Answer» E. | |
| 3413. |
Two lenses of power +12 and - 2 diopters are placed in contact. What will the focal length of combination [MP PET 1990; MNR 1987; MH CET (Med.) 2001; UPSEAT 2000; Pb. PMT 2003] |
| A. | 10 cm |
| B. | 12.5 cm |
| C. | 16.6 cm |
| D. | 8.33 cm |
| Answer» B. 12.5 cm | |
| 3414. |
The focal length of a convex lens depends upon [AFMC 1994] |
| A. | Frequency of the light ray |
| B. | Wavelength of the light ray |
| C. | Both (a) and (b) |
| D. | None of these |
| Answer» C. Both (a) and (b) | |
| 3415. |
Focal length of a convex lens of refractive index 1.5 is 2 cm. Focal length of lens when immersed in a liquid of refractive index of 1.25 will be [CBSE PMT 1993] |
| A. | 10 cm |
| B. | 2.5 cm |
| C. | 5 cm |
| D. | 7.5 cm |
| Answer» D. 7.5 cm | |
| 3416. |
Focal length of a converging lens in air is R. If it is dipped in water of refractive index 1.33, then its focal length will be around (Refractive index of lens material is 1.5) [RPMT 1997; EAMCET (Med.) 1995] |
| A. | R |
| B. | 2R |
| C. | 4R |
| D. | R / 2 |
| Answer» D. R / 2 | |
| 3417. |
The focal length of a combination of lenses formed with lenses having powers of + 2.50 D and - 3.75 D will be [RPMT 1997] |
| A. | - 20 cm |
| B. | - 40 cm |
| C. | - 60 cm |
| D. | - 80 cm |
| Answer» E. | |
| 3418. |
A convex lens [RPMT 1997] |
| A. | Converges light rays |
| B. | Diverges light rays |
| C. | Form real images always |
| D. | Always forms virtual images |
| Answer» B. Diverges light rays | |
| 3419. |
A biconvex lens with equal radii curvature has refractive index 1.6 and focal length 10 cm. Its radius of curvature will be [MP PET 2003] |
| A. | 20 cm |
| B. | 16 cm |
| C. | 10 cm |
| D. | 12 cm |
| Answer» E. | |
| 3420. |
A achromatic combination is made with a lens of focal length \[f\] and dispersive power \[\omega \] with a lens having dispersive power of \[2\omega \]. The focal length of second will be [RPET 1997] |
| A. | 2 f |
| B. | \[f/2\] |
| C. | \[-f/2\] |
| D. | ? 2 f |
| Answer» E. | |
| 3421. |
The image distance of an object placed 10 cm in front of a thin lens of focal length + 5 cm is [SCRA 1994] |
| A. | 6.5 cm |
| B. | 8.0 cm |
| C. | 9.5 cm |
| D. | 10.0 cm |
| Answer» E. | |
| 3422. |
The distance between an object and the screen is 100 cm. A lens produces an image on the screen when placed at either of the positions 40 cm apart. The power of the lens is [SCRA 1994] |
| A. | \[\approx \] 3 dioptres |
| B. | \[\approx \] 5 dioptres |
| C. | \[\approx \] 7 diopters |
| D. | \[\approx \] 9 diopters |
| Answer» C. \[\approx \] 7 diopters | |
| 3423. |
An object is placed first at infinity and then at 20 cm from the object side focal plane of the convex lens. The two images thus formed are 5 cm apart. The focal length of the lens is [SCRA 1994] |
| A. | 5 cm |
| B. | 10 cm |
| C. | 15 cm |
| D. | 20 cm |
| Answer» C. 15 cm | |
| 3424. |
Two similar plano-convex lenses are combined together in three different ways as shown in the adjoining figure. The ratio of the focal lengths in three cases will be |
| A. | 2 : 2 : 1 |
| B. | 1 : 1 : 1 |
| C. | 1 : 2 : 2 |
| D. | 2 : 1 : 1 |
| Answer» C. 1 : 2 : 2 | |
| 3425. |
A thin lens made of glass of refractive index 1.5 has a front surface + 11 D power and back surface - 6 D. If this lens is submerged in a liquid of refractive index 1.6, the resulting power of the lens is [SCRA 1994] |
| A. | -0.5 D |
| B. | + 0.5 D |
| C. | - 0.625 D |
| D. | + 0.625 D |
| Answer» D. + 0.625 D | |
| 3426. |
A double convex lens is made of glass of refractive index 1.5. If its focal length is 30 cm, then radius of curvature of each of its curved surface is [Bihar CEET 1995] |
| A. | 10 cm |
| B. | 15 cm |
| C. | 18 cm |
| D. | None of these |
| Answer» E. | |
| 3427. |
A convex lens of focal length 0.5 m and concave lens of focal length 1 m are combined. The power of the resulting lens will be [CPMT 1999; JIPMER 2000] |
| A. | 1 D |
| B. | - 1 D |
| C. | 0.5 D |
| D. | -0.5 D |
| Answer» B. - 1 D | |
| 3428. |
A plane convex lens is made of refractive index 1.6. The radius of curvature of the curved surface is 60 cm. The focal length of the lens is [CBSE PMT 1999; Pb. PMT 1999; BHU 2001; Very Similar to BHU 2003] |
| A. | 50 cm |
| B. | 100 cm |
| C. | 200 cm |
| D. | 400 cm |
| Answer» C. 200 cm | |
| 3429. |
An object of height 1.5 cm is placed on the axis of a convex lens of focal length 25 cm. A real image is formed at a distance of 75 cm from the lens. The size of the image will be [MP PET 1999] |
| A. | 4.5 cm |
| B. | 3.0 cm |
| C. | 0.75 cm |
| D. | 0.5 cm |
| Answer» C. 0.75 cm | |
| 3430. |
A lens of refractive index \[n\] is put in a liquid of refractive index \[n'\] of focal length of lens in air is \[f\], its focal length in liquid will be [MP PET 1999] |
| A. | \[-\frac{fn'(n-1)}{n'-n}\] |
| B. | \[-\frac{f(n'-n)}{n'(n-1)}\] |
| C. | \[-\frac{n'(n-1)}{f(n'-n)}\] |
| D. | \[\frac{fn'\,\,n}{n-n'}\] |
| Answer» B. \[-\frac{f(n'-n)}{n'(n-1)}\] | |
| 3431. |
An equiconvex lens of glass of focal length 0.1 metre is cut along a plane perpendicular to principle axis into two equal parts. The ratio of focal length of new lenses formed is [MP PET 1999; DPMT 2000] |
| A. | 1 : 1 |
| B. | 1 : 2 |
| C. | 2 : 1 |
| D. | 2 :\[\frac{1}{2}\] |
| Answer» B. 1 : 2 | |
| 3432. |
The plane surface of a plano-convex lens of focal length f is silvered. It will behave as [MP PMT/PET 1998] |
| A. | Plane mirror |
| B. | Convex mirror of focal length 2\[f\] |
| C. | Concave mirror of focal length \[f/2\] |
| D. | None of the above |
| Answer» D. None of the above | |
| 3433. |
A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of combination is [IIT-JEE 1982; AFMC 1997; CBSE PMT 2000; RPMT 2003] |
| A. | - 1.5 D |
| B. | - 6.5 D |
| C. | + 6.5 D |
| D. | + 6.67 D |
| Answer» B. - 6.5 D | |
| 3434. |
A thin double convex lens has radii of curvature each of magnitude 40 cm and is made of glass with refractive index 1.65. Its focal length is nearly [MP PMT 1997] |
| A. | 20 cm |
| B. | 31 cm |
| C. | 35 cm |
| D. | 50 cm |
| Answer» C. 35 cm | |
| 3435. |
The dispersive powers of glasses of lenses used in an achromatic pair are in the ratio 5 : 3. If the focal length of the concave lens is 15 cm, then the nature and focal length of the other lens would be [MP PET 1997] |
| A. | Convex, 9 cm |
| B. | Concave, 9 cm |
| C. | Convex, 25 cm |
| D. | Concave, 25 cm |
| Answer» B. Concave, 9 cm | |
| 3436. |
Two lenses have focal lengths \[{{f}_{1}}\] and \[{{f}_{2}}\] and their dispersive powers are \[{{\omega }_{1}}\] and \[{{\omega }_{2}}\] respectively. They will together form an achromatic combination if |
| A. | \[{{\omega }_{1}}{{f}_{1}}={{\omega }_{2}}{{f}_{2}}\] |
| B. | \[{{\omega }_{1}}{{f}_{2}}+{{\omega }_{2}}{{f}_{1}}=0\] |
| C. | \[{{\omega }_{1}}+{{f}_{1}}={{\omega }_{2}}+{{f}_{2}}\] |
| D. | \[{{\omega }_{1}}-{{f}_{1}}={{\omega }_{2}}-{{f}_{2}}\] |
| Answer» C. \[{{\omega }_{1}}+{{f}_{1}}={{\omega }_{2}}+{{f}_{2}}\] | |
| 3437. |
A plano convex lens is made of glass of refractive index 1.5. The radius of curvature of its convex surface is R. Its focal length is [RPET 2003] |
| A. | R/ 2 |
| B. | R |
| C. | 2R |
| D. | 1.5 R |
| Answer» D. 1.5 R | |
| 3438. |
Two thin lenses of focal lengths \[{{f}_{1}}\] and \[{{f}_{2}}\] are in contact and coaxial. The combination is equivalent to a single lens of power [MP PET 1996, 98; MP PMT 1998; DCE 2000; UP SEAT 2005] |
| A. | \[{{f}_{1}}+{{f}_{2}}\] |
| B. | \[\frac{{{f}_{1}}{{f}_{2}}}{{{f}_{1}}+{{f}_{2}}}\] |
| C. | \[\frac{1}{2}({{f}_{1}}+{{f}_{2}})\] |
| D. | \[\frac{{{f}_{1}}+{{f}_{2}}}{{{f}_{1}}{{f}_{2}}}\] |
| Answer» E. | |
| 3439. |
A convex lens of focal length 12 cm is made of glass of \[\mu =\frac{3}{2}\]. What will be its focal length when immersed in liquid of \[\mu =\frac{5}{4}\] [MP PMT 1995, 2003] |
| A. | 6 cm |
| B. | 12 cm |
| C. | 24 cm |
| D. | 30 cm |
| Answer» B. 12 cm | |
| 3440. |
A lens (focal length 50 cm) forms the image of a distant object which subtends an angle of 1 milliradian at the lens. What is the size of the image [MP PMT 1995] |
| A. | 5 mm |
| B. | 1 mm |
| C. | 0.5 mm |
| D. | 0.1 mm |
| Answer» D. 0.1 mm | |
| 3441. |
In the figure, an air lens of radii of curvature 10 cm (\[{{R}_{1}}\] = \[{{R}_{2}}\] = 10 cm) is cut in a cylinder of glass\[(\mu =1.5)\]. The focal length and the nature of the lens is [MP PET 1995; Pb. PET 2000] |
| A. | 15 cm, concave |
| B. | 15 cm, convex |
| C. | \[\infty \], neither concave nor convex |
| D. | 0, concave |
| Answer» B. 15 cm, convex | |
| 3442. |
A convex lens forms a real image of a point object placed on its principal axis. If the upper half of the lens is painted black, the image will [MP PET 1995] |
| A. | Be shifted downwards |
| B. | Be shifted upwards |
| C. | Not be shifted |
| D. | Shift on the principal axis |
| Answer» D. Shift on the principal axis | |
| 3443. |
The focal length of convex lens is 30 cm and the size of image is quarter of the object, then the object distance is [AFMC 1995] |
| A. | 150 cm |
| B. | 60 cm |
| C. | 30 cm |
| D. | 40 cm |
| Answer» B. 60 cm | |
| 3444. |
A diminished image of an object is to be obtained on a screen 1.0 m from it. This can be achieved by appropriately placing [IIT JEE 1995] |
| A. | A convex mirror of suitable focal length |
| B. | A concave mirror of suitable focal length |
| C. | A concave lens of suitable focal length |
| D. | A convex lens of suitable focal length less than 0.25 m |
| Answer» E. | |
| 3445. |
If the central portion of a convex lens is wrapped in black paper as shown in the figure [Manipal MEE 1995; KCET 2001] |
| A. | No image will be formed by the remaining portion of the lens |
| B. | The full image will be formed but it will be less bright |
| C. | The central portion of the image will be missing |
| D. | There will be two images each produced by one of the exposed portions of the lens |
| Answer» C. The central portion of the image will be missing | |
| 3446. |
A plano convex lens \[(f=20cm)\]is silvered at plane surface. Now f will be [BHU 1995; DPMT 2001; MP PMT 2005] |
| A. | 20 cm |
| B. | 40 cm |
| C. | 30 cm |
| D. | 10 cm |
| Answer» E. | |
| 3447. |
An achromatic combination of lenses is formed by joining [BHU 1995; Pb. PMT 2000, 04] |
| A. | 2 convex lenses |
| B. | 2 concave lenses |
| C. | 1 convex lens and 1 concave lens |
| D. | Convex lens and plane mirror |
| Answer» D. Convex lens and plane mirror | |
| 3448. |
A combination of two thin lenses with focal lengths \[{{f}_{1}}\] and \[{{f}_{2}}\] respectively forms an image of distant object at distance 60 cm when lenses are in contact. The position of this image shifts by 30 cm towards the combination when two lenses are separated by 10 cm. The corresponding values of \[{{f}_{1}}\] and \[{{f}_{2}}\] are [AIIMS 1995] |
| A. | \[30\] \[cm,\]\[-60\]\[cm\] |
| B. | \[20\]\[cm\], \[-30\]\[cm\] |
| C. | \[15\]\[cm,\] \[-20\]\[cm\] |
| D. | \[12\] \[cm,\] \[-15\]\[cm\] |
| Answer» C. \[15\]\[cm,\] \[-20\]\[cm\] | |
| 3449. |
Two lenses of power 6D and ? 2D are combined to form a single lens. The focal length of this lens will be [MP PET 2003] |
| A. | \[\frac{3}{2}\] m |
| B. | \[\frac{1}{4}\]\[m\] |
| C. | 4 m |
| D. | \[\frac{1}{8}\]\[m\] |
| Answer» C. 4 m | |
| 3450. |
A lens is placed between a source of light and a wall. It forms images of area \[{{A}_{1}}\] and \[{{A}_{2}}\] on the wall for its two different positions. The area of the source or light is [CBSE PMT 1995] |
| A. | \[\frac{{{A}_{1}}+{{A}_{2}}}{2}\] |
| B. | \[{{\left[ \frac{1}{{{A}_{1}}}+\frac{1}{{{A}_{2}}} \right]}^{-1}}\] |
| C. | \[\sqrt{{{A}_{1}}{{A}_{2}}}\] |
| D. | \[{{\left[ \frac{\sqrt{{{A}_{1}}}+\sqrt{{{A}_{2}}}}{2} \right]}^{2}}\] |
| Answer» D. \[{{\left[ \frac{\sqrt{{{A}_{1}}}+\sqrt{{{A}_{2}}}}{2} \right]}^{2}}\] | |