Tiêu đề 01, 02 & 03_DPP Ray Optics Physics.pdf ✅

1 | P a g e DPP-01 Batch: Achiever Topic : Ray Optics 1. When a light ray from a rarer medium is refracted into a denser medium, its: (1) Speed increases, wavelength increases (2) Speed decreases, wavelength increases (3) Speed increases, wavelength decreases (4) Speed decreases, wavelength decreases 2. A red colour in air has wavelength 760 nm when light passes through water of refractive index 4 n 3     =   , wavelength becomes 570 nm. (wavelength of yellow colour in air is 570 nm). Then colour of red light in water is: (1) Red (2) Green (3) Yellow (4) Blue 3. A ray of light is incident from a rarer medium (μ = 1.5) into a denser medium. If the angle of incidence and refraction are respectively 60° and 45°, then calculate the refractive index of the denser medium: (1) 1 (2) 1.73 (3) 1.5 (4) 1.84 4. Figure (a) and (b) show refraction of a ray in air incident at 60° with the normal to a glass air and water air interface, respectively. What is the angle of refraction in glass when the angle of incidence in water is 45° with the normal to a water-glass interface figure (c): (1) 38° (2) 60° (3) 90° (4) 52° 5. A ray of light passes from glass having a refractive index of 1.6, to air. The angle of incidence for which the angle of refraction is twice the angle of incidence is: (1) –1 4 sin 5       (2) –1 4 cos 5       (3) –1 5 sin 8       (4) –1 5 cos 8       6. Monochromatic light of frequency 5 × 1014Hz travelling in vacuum enters a medium of refractive index 1.5. Its wavelength in the medium is: (1) 4000 Å (2) 5000 Å (3) 6000 Å (4) 5500 Å 7. A ray of light is incident on the surface of separation of a medium at an angle 45° and is refracted in the medium at an angle 30°. What will be the velocity of light in the medium? (1) 1.96 × 108 m/s (2) 2.12 × 108 m/s (3) 3.18 × 108 m/s (4) 3.33 × 108 m/s 8. A ray of light AO is incident on the surface of oil. Reflected part of this ray OB and refracted part OC are mutually perpendicular as shown. Find refractive index of oil: (1) 3 (2) 2 3 (3) 1 3 (4) 2 Daily Practice Problems (PHYSICS)
2 | P a g e 9. What is the time taken (in seconds), to cross a glass of thickness 4 mm and μ = 3, by light? (1) 4 × 10–11 (2) 2 × 10–11 (3) 16 × 10–11 (4) 8 × 10–10 10. What is the time taken, to cross a glass of thickness t and refractive index , by light if it is incident normally on the slab? (c = speed of light) (1) t c  (2) c t (3) t c (4) t c DPP-02 1. A small pin fixed on a table top is viewed from above from a distance of 50 cm. by what distance would the pin appear to be raised if it is viewed from the same point through a 15 cm thick glass slab held parallel to the table? (glass =1.5) (1) 10 cm (2) 25 cm (3) 5 cm (4) None of these 2. A microscope is focused on a coin lying at the bottom of a beaker. The microscope is now raised by 1 cm. To what depth should water be poured into the beaker so that the coin is again in focus? (The refractive index of water is 4 3 ) (1) 1 cm (2) 4/3 cm (3) 3 cm (4) 4 cm 3. A glass slab ( = 1.5) of thickness 2 cm is placed on a spot. The shift of spot if it is viewed from top: (1) 2 3 cm (2) 4 3 cm (3) 1 3 cm (4) 5 3 cm 4. A plane glass is kept over a coloured word ‘VIBGYOR’, where colour of letters as same as the colours in white light start by letter, the letter which appears least raised is: (1) R (2) Y (3) O (4) V 5. A light ray is travelling from air to glass. The reflected and refracted rays are perpendicular to each other. If the angle of incidence in air is i the refractive index of glass is: (1) sin i (2) cos i (3) tan i (4) cot i 6. A vessel of depth x is half-filled with oil of refractive index μ2 and the other half is filled with water of refractive index μ1 . The apparent depth of the vessel when viewed from above is: (1) ( 1 2 ) 1 2 x 2  +   +  (2) ( ) 1 2 1 2 x 2    +  (3) ( ) 1 2 1 2 x   +  (4) ( 1 2 ) 1 2 x 2  +    7. To a fish in water, a bird in air appears to be at 30 cm from the surface. If aμw = 4 3 , then the true distance of the bird from the surface is: (1) 40 cm (2) 22.5 cm (3) 80 cm (4)None of the above 8. 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 opposite face is 4 cm. The refractive index of material of cube is: (1) 2.0 (2) 1.5 (3) 1.6 (4) 2.5 9. A convergent beam is incident on two slabs placed in contact with each other (as shown) where will ray finally converge?  = 3/2 14 cm 6 cm  = 2 4 cm object (1) 14 cm (2) 4 cm (3) 18 cm (4) 16 cm

4 | P a g e 6. The wavelength of light in two liquids ’x’ and ‘y’ is 3500Å and 7000Å, then the critical angle will be: (1) 60° (2) 45° (3) 30° (4) 15° 7. A light ray is incident perpendicular to one face of a 90° prism and is totally internally reflected at the glass-air interface. If the angle of reflection is 45°, we conclude that the refractive index : (1)  < 1 2 (2)  > 2 (3)  > 1 2 (4)  < 2 8. Figure shows a cross section of a ‘light pipe’ made of a glass fibre of refractive index 2 . The outer covering of the pipe is made of a material of refractive index 3 2 . What is maximum angle of the incident ray with the axis of the pipe for which total internal reflections inside the pipe take place: (1) 45° (2) 66° (3) 80° (4) 90° 9. In the above problem, what is the answer if there is no outer covering of the pipe: (1) 30° (2) 45° (3) 90° (4) None of these 10. For the given incident ray as shown in figure, the condition of total internal reflection of this ray the required refractive index of prism will be: 45o incident ray (1) 3 1 2 + (2) 2 1 2 + (3) 3 2 (4) 7 6 11. A small bulb is placed at the bottom of a tank containing water to a depth of 80 cm. What is the area of the surface of water through which light from the bulb can emerge out: (water =1.33) (1) 2.54 m2 (2) 3.71 m2 (3) 1.11 m2 (4) 4 m2 12. With respect to air, critical angle in a medium for light of red colour [1 ] is . Other facts remaining same, critical angle for light of yellow colour [2 ] will be : (1)  (2) More than  (3) Less than  (4) 1 2   13. If a source of white light kept inside the water. If an observer outside it see yellow light coming out of water. Then which of following is coming necessarily coming out? (1) Violet (2) Blue (3) Indigo (4) orange ANSWER KEY DPP - 01 1. (4) 2. (1) 3. (4) 4. (3) 5. (2) 6. (1) 7. (2) 8. (1) 9. (1) 10. (1) DPP - 02 1. (3) 2. (4) 3. (1) 4. (1) 5. (3) 6. (4) 7. (2) 8. (2) 9. (3) 10. (4) 11. (2) 12. (4) DPP - 03 1. (1) 2. (2) 3. (3) 4. (2) 5. (3) 6. (3) 7. (2) 8. (1) 9. (3) 10. (3) 11. (1) 12. (3) 13. (4) 45° 45°