Tiêu đề 23 JUNE PW PAPER.pdf ✅

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PHYSICS 1. A watch shows time as 3: 25 when seen through a mirror, time appeared will be (A) 8:35 (B) 9:35 (C) 7 :35 (D) 8: 25 2. If an observer is walking away from the plane mirror with 6 m/sec. Then the velocity of the image with respect to observer will be (A) 6 m/sec (B) –6 m/sec (C) 12 m/sec (D) 3 m/sec 3. A ray of light is incident at 50° on the middle of one of the two mirrors arranged at an angle of 60° between them. The ray then touches the second mirror, get reflected back to the first mirror, making an angle of incidence of (A) 50° (B) 60° (C) 70° (D) 80° 4. At what angle of incidence, the light reflected from a glass slab will become completely polarised, if the angle of refraction is 33.6o ? (A) 90 (B) 0 (C) 56.4 (D) 46.4 5. The focal length of a concave mirror is 50 cm. Where an object be placed so that its image is two times and inverted (A) 75 cm (B) 72 cm (C) 63 cm (D) 50 cm 6. The ratio of the refractive index of red light to blue light in air is (A) Less than unity (B) Equal to unity (C) Greater than unity (D) Less as well as greater than unity depending upon the experimental arrangement 7. The refractive index of a certain glass is 1.5 for light whose wavelength in vacuum is 6000 Å. The wavelength of this light when it passes through glass is (A) 4000 Å (B) 6000 Å (C) 9000 Å (D) 15000 Å 8. When a light wave goes from air into water, the quality that remains unchanged is its (A) Speed (B) Amplitude (C) Frequency (D) Wavelength 9. If the critical angle for total internal reflection from a medium to vacuum is 30°, the velocity of light in the medium is (A) 8 3 10  m/s (B) 8 1.5 10  m/s (C) 8 6 10  m/s (D) 8 3 10  m/s 10. A transparent cube of 15 cm edge contains a small air bubble. Its apparent depth when viewed through one face is 6 cm and when viewed through the opposite face is 4 cm. Then the refractive index of the material of the cube is (A) 2.0 (B) 2.5 (C) 1.6 (D) 1.5 11. Path of two parallel light rays is shown in a transparent sphere. Refractive index of the sphere material is: (A) 1.2 (B) 1.3 (C) 1.4 (D) 1.5 12. The image of an object, formed by a plano-convex lens at a distance of 8 m behind the lens, is real and is one-third the size of the object. The wavelength of light inside the lens is 2/3 times the wavelength in free space. The radius of the curved surface of the lens is: (A) 1 m (B) 2 m (C) 3 m (D) 6 m 13. The resolution limit of eye is 1 min. At a distance x km from the eye two persons stand with a lateral separation of 3m. For the two persons to be just resolved by the naked eye, x should be: (A) 10 km (B) 20 km (C) 15 km (D) 30 km 14. The focal lengths of the objective and the eye piece of a compound microscope are 2.0 cm and 3.0 cm respectively. The distance between the objective and the eye piece is 15 cm. The final image formed by the eye-piece is at infinity. The two lenses are thin, the distance in cm of the object and the image produced by the objective measured from the objective lens are respectively. (A) 2.4 and 12.0 (B) 2.4 and 15.0 (C) 2.3 and 12.0 (D) 2.3 and 3.0 PW-AITS_NT-10
15. The maximum intensity of fringes in Young‟s experiment is I. If one of the slit is closed, then the intensity at that place becomes I0. Which of the following relation is true? (A) I = I0 (B) I = 2I0 (C) I = 4I0 (D) There is no relation between I and I0 16. An object 5 cm tall is placed 10 cm from a convex mirror of radius of curvature 30 cm. What is the nature and size of the image: (A) real, 3 cm (B) virtual, 7.5 cm (C) virtual, 3 cm (D) real, 7.5 cm 17. The near point of a person is 50 cm and the far point is 1.5 m. The spectacles required for reading purpose and for seeing distant objects are respectively: (A) 2 2D, D 3   (B) 2 D, 2D 3   (C) 2 2D, D 3   (D) 2 D, 2D 3   18. In Young‟s double slit experiment, the distance between the two slits is 0.1 mm and the wavelength of light used is 4 × 10–7m. If the width of the fringe on the screen is 4 mm, the distance between screen and slit is (A) 0.1 mm (B) 1 cm (C) 0.1 cm (D) 1 m 19. A beam of light of wavelength 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between the first dark fringes on either side of the central bright fringe is (A) 1.2 mm (B) 1.2 cm (C) 2.4 cm (D) 2.4 mm 20. A diver at a depth of 12m in water (   4 / 3) sees the sky in a cone of semi-vertical angle (A) 1 sin (4 / 3)  (B) 1 tan (4 / 3)  (C) 1 sin (3 / 4)  (D) 90° 21. A thin lens focal length 1 f and its aperture has diameter d. It forms an image of intensity I. Now the central part of the aperture upto diameter d 2 is blocked by an opaque paper. The focal length and image intensity will change to (A) f 2 and I 2 (B) f and I 4 (C) 3f 4 and I 2 (D) f and 3I 4 22. 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 (A) – 1.5 D (B) – 6.5 D (C) + 6.5 D (D) + 6.67 D 23. If in a plano-convex lens, the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm, then the refractive index of the material of lens will be (A) 1.5 (B) 1.66 (C) 1.33 (D) 3 24. An object is placed at a distance of 20 cm from a convex lens of focal length 10 cm. The image is formed on the other side of the lens at a distance (A) 20 cm (B) 10 cm (C) 40 cm (D) 30 cm 25. A double convex lens of focal length 20 cm is made of glass of refractive index 3 / 2. When placed completely in water a w ( 4 / 3)   , its focal length will be (A) 80 cm (B) 15 cm (C) 17.7 cm (D) 22.5 cm 26. In the figure, an air lens of radii of curvature 10 cm ( R1 = R2 = 10 cm) is cut in a cylinder of glass ( 1.5)  . The focal length and the nature of the lens is Glas s Air (A) 15 cm, concave (B) 15 cm, convex (C)  , neither concave nor convex (D) 0, concave 27. A convex lens has a focal length f. It is cut into two parts along the dotted line as shown in the figure. The focal length of each part will be (A) f 2 (B) f (C) 3 f 2 (D) 2f 28. A point object O is placed in front of a glass rod having spherical end of radius of curvature 30 cm. The image would be formed at (g = 3/2) (A) 30 cm left (B) Infinity
(C) 1 cm to the right (D) 18 cm to the left 29. When light rays are incident on a prism at an angle of 45°, the minimum deviation is obtained. If refractive index of the material of prism is 2 , then the angle of prism will be (A) 30° (B) 40° (C) 50° (D) 60° 30. Angle of a prism is 30° and its refractive index is 2 and one of the surface is silvered. At what angle of incidence, a ray should be incident on one surface so that after reflection from the silvered surface, it retraces its path (A) 30° (B) 60° (C) 45° (D) 1 sin 1.5  31. A thin prism P1 with angle 4° and made from glass of refractive index 1.54 is combined with another thin prism P2 made from glass of refractive index 1.72 to produce dispersion without deviation. The angle of prism P2 is (A) 2.6° (B) 3° (C) 4° (D) 5.33° 32. Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are (A) 5I and I (B) 5I and 3I (C) 9I and I (D) 9I and 3I 33. If two waves represented by y 4sin t 1   and 2 y 3sin t 3           interfere at a point, the amplitude of the resulting wave will be about (A) 7 (B) 6 (C) 5 (D) 3.5 34. Monochromatic green light of wavelength 5 × 10– 7 m illuminates a pair of slits 1 mm apart. The separation of bright lines on the interference pattern formed on a screen 2 m away is (A) 0.25 mm (B) 0.1 mm (C) 1.0 mm (D) 0.01 mm 35. In Young's experiment, the distance between the slits is reduced to half and the distance between the slit and screen is doubled, then the fringe width (A) Will not change (B) Will become half (C) Will be doubled (D) Will become four times 36. In a Young's double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index 4/3 without disturbing the geometrical arrangement, the new fringe width will be (A) 0.30 mm (B) 0.40 mm (C) 0.53 mm (D) 450 micron 37. In Young‟s experiment, monochromatic light is used to illuminate the two slits A and B. Interference fringes are observed on a screen placed in front of the slits. Now if a thin glass plate is placed normally in the path of the beam coming from the slit (A) The fringes will disappear (B) The fringe width will increase (C) The fringe width will increase (D) There will be no change in the fringe width but the pattern shifts 38. What will be the angle of diffracting for the first minimum due to Fraunhoffer diffraction with sources of light of wave length 550 nm and slit of width 0.55 mm (A) 0.001 rad (B) 0.01 rad (C) 1 rad (D) 0.1 rad 39. The path difference between two interfering waves of equal intensities at a point on the screen is /4. The ratio of intensity at this point and that at the central fringe will be (A) 1 : 1 (B) 1 : 2 (C) 2 : 1 (D) 1 : 4 40. Unpolarized light of intensity 32Wm–2 passes through three polarizers such that transmission axes of the first and second polarizer makes an angle 30° with each other and the transmission axis of the last polarizer is crossed with that of the first. The intensity of final emerging light will be (A) 32 Wm–2 (B) 3 Wm–2 (C) 8 Wm–2 (D) 4 Wm–2 41. In Young‟s double-slit experiment an interference pattern is obtained on a screen by a light of wavelength 6000 Å, coming from the coherent sources S1 and S2. At certain point P on the screen