OBJECTIVE QUESTIONS FOR NEET AIIMS JIPMER www wisedane
OBJECTIVE QUESTIONS FOR NEET AIIMS JIPMER www. wisedane. com
PHYSICS RAY OPTICS SET 2 MCQ’S www. wisedane. com
Q 1. The focal length of a convex lens depends upon : A. Frequency of the light ray B. Wavelength of the light ray C. Both (A) and (B) D. None of these www. wisedane. com
ANSWER (C) EXPLANATION www. wisedane. com
Q 2. A convergent lens placed inside a vessel filled with liquid is shown in the figure below. The lens has focal length +20 cm when in air, and its material has refractive index 1. 5. if the liquid has refractive index 1. 6, the focal length of the system is A. +80 cm B. -80 cm C. -160 cm D. -100 cm www. wisedane. com
ANSWER (C) EXPLANATION www. wisedane. com
Q 3. A 1. 7 m tall person stands 1. 6 m in front of a vertical plane mirror. The height of his image will be : A. 1. 6 m B. 1. 7 m C. 0. 85 m D. 3. 4 m www. wisedane. com
ANSWER (B) EXPLANATION Ø Image formed will be of the same size as object. (properties of image formed by a plane mirror). www. wisedane. com
Q 4. A convergent lens is placed inside a vessel filled with liquid. The lens has focal length +20 cm when in air, and its material has refractive index 1. 5. if the liquid has refractive index 1. 33, the new focal length of the lens is : A. + 80 cm B. – 80 cm C. – 160 cm D. – 100 cm www. wisedane. com
ANSWER (A) EXPLANATION www. wisedane. com
Q 5. A plane glass slab is kept over various coloured letters. The letter which appears least raised is : A. Blue B. Violet C. Green D. Red www. wisedane. com
ANSWER (D) EXPLANATION www. wisedane. com
www. wisedane. com
ANSWER (A) EXPLANATION www. wisedane. com
Q 7. A light beam passes from air into liquid and is deviated by 150 when the angle of incidence is 600. What is the index of refraction of the liquid ? www. wisedane. com
ANSWER (D) EXPLANATION When the ray deviates by 15 o, then, www. wisedane. com
Q 8. 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 position. The area of source is : www. wisedane. com
ANSWER (C) EXPLANATION we have, object size www. wisedane. com
Q 9. which source is associated with a line emission spectrum ? A. Red traffic light B. Sun C. Electric fire D. Neon street light www. wisedane. com
ANSWER (D) EXPLANATION Ø Neon lights are a type of cold cathode gas-discharge light. A neon tube light is a sealed glass tube with a metal electrode at each end, filled with one of a number of gases at low pressure. Ø A high potential of several thousand volts applied to the electrodes ionizes the gas in the tube, causing it to emit colored light. The color of the light depends on the gas in the tube. Ø Neon lights were named for neon, a noble gas which gives off a popular orange light, but other gases and chemicals are used to produce other colors, such as hydrogen (red), helium (yellow), carbon dioxide (white), and mercury (blue). www. wisedane. com
Q 10. How should people wearing their spectacles work with a microscope ? A. They should keep on wearing their spectacles B. They should take off their spectacles C. They may either put on their spectacles or they may take off their spectacles; it makes no difference D. They cannot use the microscope at all www. wisedane. com
ANSWER (b) EXPLANATION Ø As the defect of eye can be rectified by adjusting the microscope, they should take off their spectacles. www. wisedane. com
Q 11. A mark ‘A’ placed on the surface of a glass sphere is viewed through glass from a point directly opposite, Radius of sphere = 10 cm. Refractive index of glass is 1. 5. Which one of the following statements is correct ? A. The image formed is real and at a distance of 0. 4 m from the eye B. The image formed is virtual and at a distance of 0. 2 m from the eye C. The image formed is virtual and at a distance 0. 3 m from the centre of the sphere D. The image formed is real and at a distance of 0. 2 m from point A www. wisedane. com
ANSWER (C) EXPLANATION www. wisedane. com
Q 12. Immiscible transparent liquids A, B, C, D and E are placed in rectangular container of glass with the liquids making layers according to their densities. The refractive index of the liquids is shown in the following figure. The container is illuminated from the side and a small piece of glass having refractive index 1. 61 is gently dropped into the liquid layers. The glass piece, as it descends downwards, wil not be visible in (refer figure): A. Liquid A and B only B. Liquid C only C. Liquid D and E D. Liquid A, B, D and E www. wisedane. com
ANSWER (B) EXPLANATION Ø Glass piece will not be visible in the layer having the same value of refractive index as that of glass piece i. e. the layer C www. wisedane. com
Q 13. A convex lens of glass is immersed in water compared to its power in air, its power in water will : A. Diminish B. Increase C. Remain the same D. Diminish for red light and increase for blue light www. wisedane. com
ANSWER (A) EXPLANATION www. wisedane. com
Q 14. The focal length of a convex lens is 30 cm and the size of the image is half of the object. The object distance is : A. 60 cm B. 90 cm C. 30 cm D. 40 cm www. wisedane. com
ANSWER (B) EXPLANATION www. wisedane. com
Q 15. A lens behaves as a converging lens in air and a diverging lens in water. The refractive index of the material is - A. Equal to unity B. Equal to 1. 33 C. Between unity and 1. 33 D. Greater than 1. 33 www. wisedane. com
ANSWER (C) EXPLANATION Ø Between unity and 1. 33, because refractive index of water is 1. 33. www. wisedane. com
Q 16. In the displacement method of finding focal length of a convex lens, I 1 and I 2 are the sizes of the images respectively for the two position of the lens. The size of the object is : www. wisedane. com
ANSWER (C) EXPLANATION www. wisedane. com
Q 17. fv and f. R are the focal length of a convex lens for violet and red light, respectively, and Fv and FR are the focal length of a concave lens for violet and red light, respectively. Which one of the following relations is correct ? www. wisedane. com
ANSWER (C) EXPLANATION www. wisedane. com
Q 18. A thin convex lens of focal length 30 cm and refractive index 1. 5 is placed on a horizontal plane mirror. It is found that an object, at a height ‘h’ above the lens, has no parallax with its image. The h is : A. 60 cm B. 30 cm C. 45 cm D. 20 cm www. wisedane. com
ANSWER (B) EXPLANATION Ø When rays of light are incident normal to the plane mirror, they are rebounced back. Ø So if the object is at the focus of the convex lens, then after refraction through the lens, rays of light become normal to the plane mirror which makes them rebounce and form the image at the same point of the object. Ø It shows height of the object is equal to focal length of the convex lens i. e. 30 cm. www. wisedane. com
Q 19. Time taken by the sunlight to pass through a window of thickness 4 mm whose refractive index is 1. 5 is : www. wisedane. com
ANSWER (C) EXPLANATION www. wisedane. com
Q 20. Two lenses whose powers are +2 D and -4 D respectively are placed in contact. The power of the combination is : A. – 2 D B. – 4 D C. + 2 D D. + 4 D www. wisedane. com
ANSWER (A) EXPLANATION www. wisedane. com
More Mcq’s For All Subject Please Log on to http: //www. wisedane. com/ Exclusive Portal For Online Coaching NEET AIIMS JIPMER
- Slides: 43
