1. A solution turns red litmus blue, its pH is likely to be …….
A. 1 B. 4 C. 5 D. 10
2. Colour of methyl orange in alkali conditions?
A. Orange B. Yellow C. Red D. Blue
3. This is used as olfactory indicator ……
A. coloured petals B. onion C. petunia D. litmus
4. Metal oxides are …….
A. basic in nature B. acidic in nature C. neutral in nature D. None of the above
5. The process of dissolving an acid or a base in water is …… process.
A. endothermic B. exothermic C. oxidation D. reduction
6. This salt is mined like coal ……
A. acid salt B. base salt C. neutral salt D. rock salt
7. In pH the letter p stands for …….
A. Potentz B. Potential C. Pre D. Post
8. Pickles are not stored in these vessels ……
A. glass B. plastic C. brass D. ceramic
9. Radius of curvature of a spherical mirror r = ……
A. f B. f/2 C. 2f D. 2f/3
10. …… mirror used in solar cookers.
A. Plane B. Convex C. Concave D. Spherical
11. In car-head lights, the spherical mirrors are in the shape of ……
A. concave B. convex C. ellipsoidal D. parabolic
12. This is a divergent mirror …….
A. concave mirror B. convex mirror C. plane mirror D. parabolic mirror
13. Which of the following can produce a virtual image?
A. concave mirror B. convex mirror C. plane mirror D. All the above
Answers : 1-D 2-B 3-B 4-A 5-B 6-D 7-A 8-C 9-C 10-C 11-D 12-B 13-D
1. The refractive index of glass with respect to air is 2. Then the critical angle of glass – air interface is ……..
a. 0° b. 45° c. 30° d. 60°
2. When a light ray travels from a rarer medium (air) to a denser medium (glass) and if the angle of incidence is i and angle of refraction is r, then …….
a. i > r b. i < r c. i = r d. None of the above
3. This is the coloured part we see in the eye.......
a. pupil b. cornea c. eye-lens d. iris
4. The unit of refractive index is ......
a. m/s b. cm/s c. No units d. None of the above
5. Kerosene is optically ....... than water.
a. diluted b. denser c. heavier d. rarer
6. The refractive index of benzene is .......
a. 0.15 b. 1.5 c. 1.33 d. 0.133
7. Optical fibres work on the principle of .......
a. reflection b. refraction c. internal reflection d. total internal reflection
8. The refractive index of air increases with....
a. hotness b. humidity c. density d. All the above
9. The incident and emergent rays in the case of glass slab are ........
a. perpendicular b. inclined c. parallel d. coincident
10. Mirage is an example of .....
a. reflection b. refraction c. optical illusion d. optical magic
11. Which one of the materials cannot be used to make a lens?
a. water b. glass c. plastic d. clay
12. If f = + 0.5 m for a lens, then its power is ......
a. 0.5 dioptre b. 5 dioptre c. +2 dioptre d. + 1 dioptre
13. We can see ....... image with our eyes.
a. virtual b. real c. inverted d. magnified
14. In the case of a concave lens, the image is always formed at .......
a. F b. between F and C c. beyond C d. between P and F
15. A stick held obliquely in water appears bent and short. This is due to the phenomenon of ......
a. reflection b. refraction c. scattering d. dispersion
16. A piece of transparent optical material, having one or two spherical surfaces is called .....
a. prism b. slab c. lens d. None of the above
17. The focal length of a lens depends upon ......
a. size of the object b. surrounding medium
c. distance of the object d. nature of the object
18. Rays passing through the focus of a convex lens will take a path ....... to the principal axis after refraction.
a. parallel b. perpendicular c. inclined d. None of the above
19. The mid point of a lens is called .....
a. centre of curvature b. focus c. optic centre d. principal axis
20. The value of the focal length of a lens is equal to the value of the image distance when the rays are ........
a. passing through the optic centre
b. parallel to the principal axis
c. passing through the focus
d. in all cases
21. The value of least distance of distinct vision is ......
a. 10 cm b. 15 cm c. 20 cm d. 25 cm
22. During refraction ...... will not change.
a. wavelength b. frequency
c. speed of light d. All the above
23. When objects at different distances are seen by the eye which of the following remain constant?
a. focal length of eye-lens
b. object distance from eye-lens
c. the radii of curvature of eye-lens
d. image distance from eye-lens
24. Near sightedness is called .....
a. Myopia b. Hypermetropia c. Presbyopia d. All the above
25. This colour of light has longest wavelength in the visible spectrum of light ......
a. orange b. red c. violet d. yellow
26. ...... reflection does not obey the laws of reflection.
a. regular b. irregular c. partial d. plane
27. If the power of the lens is 2D, then its focal length is ......
a. 100 cm b. 50 cm c. 25 cm d. 75 cm
28. On a hot day the sky appears .......
a. Red b. Yellow c. White d. Blue
Answers : 1-c 2-a 3-d 4-c 5-b 6-b 7-d 8-c 9-c 10-c 11-d 12-c 13-a
14-d 15-b 16-c 17-b 18-a 19-c 20-d 21-d 22-b 23-d 24-a 25-b 26-b
27-b 28-c.