1. The streaming of light beams coming from the Sun through trees is said to have suggested that light travels in straight line. The particles on the path of light beams are visible to us because
2. The flash of lightning is seen before the thunderstorm is heard. It verifies that
3. Sita, 1.5 m high, stands before a plane mirror fixed on a wall to view her full image. What should be the minimum height of the plane mirror so that Sita can view her image fully?
4. Ramesh cannot see distinctly objects kept beyond 2 m. The defect can be correct by using a lens of power
5. Which one of the following optical phenomena supports that the light is a transverse wave?
6. A rectangle ABCD is kept in front of a concave mirror of focal length f with its corners A and B being, respectively, at distances 2f and 3f from the mirror with AB along the principal axis as shown in the figure. It forms an image A'B'C'D' in front of the mirror. What is the ration of B'C' to A'D'?
7. Shown in the figure are two plane mirrors XY and YZ (XY is perpendicular to YZ) joined at their edge. Also shown is a light ray falling on one of the mirrors and reflected back parallel to its original path as a result of this arrangement. The two mirrors are now rotated by an angle θ to their new position X'YZ', as shown. As a result the new reflected ray is at an angle α from the original reflected ray. Then:
8. In the disperson of white light by a common glass prism, which one among the following is correct?
9. Which one of the following telescopes contains only mirrors?
10. Human eye can see objects at different distances with contrasting illuminations. This is due to
11. Two convex lenses have focal lengths of 50 cm and 25 cm, respectively. If these two lenses are placed in contact, then the net power of this combination will be equal to
12. The refractive index of crown glass is close to 3/2. If the speed of light in air is c, then the speed of light in the crown glass will be close to
13. The twinkling of a star is due to the atmospheric
14. What is the magnification produced by a concave lens of focal length 10 cm, when an image is formed at a distance of 5 cm from the lens?
15. Myopia is a defect in human vision where and image of a
16. Tyndall effect is a phenomenon of
17. Twinkling of stars is primarily due to the atmospheric
18. Cornea in human eye
19. Power of a lens of focal length 25 cm is
20. Spherical mirror formula relating an object distance 'u', image distance 'v' and focal length of mirror 'f' may be applied to a plane mirror when
21. Which one of the following figures correctly shows the path of a ray of light through a glass prism?
22. When a light beam falls on a triangular glass prism, a band of colours is obtained. Which one of the following statements is correct in this regard?
23. The image of an object formed by a plane mirror is