(1) Statement (1) is wrong. A bubble of water shines due to total internal reflection. (2) Statement (2) is wrong. The sudden change in direction of light, when passing from one transparent substance to another, is called refraction. (3) Statement (3) is correct. The splitting of light into different colours is called dispersion of light.

1. Statement (1) is wrong. The least distance of distinct vision for a healthy human eye is 25 cm.
   1. Statement (2) is correct. The time difference between actual sunset and apparent is 2 minutes. This happens due to atmospheric refraction.

1. Statement (1) is wrong. When one enters a dark room, one is not able to see anything but, after sometime vision improves. This is because the pupil of the eye diflates.
   1. Statement (2) is correct. In myopia, the eye lens become too thick & its focal length is reduced. The short sightedness occurs due to excessive convergence of light rays by the eye lens, it can be corrected by using a diverging lens, i.e. a concave lens.

1. Statement (1) is wrong. The colour of an opaque object is due to the colour it reflects.
   2. Statement (2) is correct. A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. It is produced because warm air has higher refractive index than cool air. 3.  Statement (3) is correct. The bending of light rays, which enter our eyes, is done by cornea of the eye.

(i) Statement (1) is wrong. CFLs are recommended to use for their energy efficiency. Rectifiers are used to convert DC to AC. (ii) Statement (2) is correct. CFL lamps contain mercury, which is very toxic to health and environment. (iii) Statement (3) is correct. LEDs use the least power (watts) per unit of light generated (lumens).

(I) Statement (1) is wrong. A camera works on the refraction of light through a convex lens. (II) Statement (2) is wrong. The process in which an eye can adapt itself to see objects at different distances is called accommodation. (III) There are three types of optical telescopes: - Refracting telescope - Uses lens to form an image - Reflecting telescope - Uses an arrangement of mirrors to form an image - Catadiopteric telescope - Uses mirrors combined with lenses to form an image

1. Statement (1) is wrong. The power of lens is generally measured in diopter.
   2. Statement (2) is wrong. Stereoscopy (3D imaging) is a technique for creating or enhancing the illusion of depth in an image by means of binocular vision.

   1. Statement (3) is wrong. Supermarket scanners emit UV radiations, which are harmful environment.

Statement (1) is wrong. Old written material, which cannot be read easily, can be read by infra red radiations. Statement (2) is correct. Yes, Gamma rays carry the maximum amount of energy, which are used in the treatment of cancer.

Statement (1) is correct. The glowing of tube light is based on the phenomenon of total reflection.

Statement (1) is correct. The light from sun takes about 8 minutes to reach the Earth.

(I) Statement (1) is wrong. If an object is placed midway between two parallel plane mirrors facing each other, the number of images that appear in the mirrors is infinity. (II) Statement (2) is correct. Magnifying glass is made of a converging lens which helps to produce an upright and magnifying image of an object. (III) Statement (3) is wrong. To get a virtual and magnified image, concave mirror is used.

Statement (1) is correct. Infrared radiations are used as signals during war as they are not visible, and they are not absorbed much in a medium.

Statement (1) is correct. Infrared rays lie just under the visible light range in the electromagnetic spectrum. The molecules of IR rays are strike to oscillate, which produce heating effect. Statement (2) is wrong. For detecting forged bank notes, UV rays are used. Some bank notes have security elements either words or images printed onto the note using non-visible dyes, which fluorescence under ultraviolet light.

Statement (1) is wrong.To view an image of yourself in a plane mirror, you will need an amount of mirror equal to one-half of your height.

Statement (2) is wrong. A convex mirror has an outward curve, meaning that the reflecting surface is focused towards the source of light falling onto it. Such mirrors create a virtual image of the object and this image is lightly diminished as compared to the object's actual size. This is why in some of the cars, the passenger side-mirror is generally inscribed with a warning, which states that “Objects in the mirror are closer than they appear”. The convex mirror produces an upright image of any object and offers a wide viewing area as compared to the plane mirror. The usage of this type of mirror can be perceived on the rear-view mirror and side-view mirror of the cars, and the motorcycles. These mirrors in the vehicles help in cutting down the blind spots as long as the object is in their focus. 

Statement (1) is correct. The photocopy machines emit UV radiations, which can cause eye problems.