7. A ray of light is travelling in a direction perpendicular to theboundary of a parallel glass slab. The ray of light:a) Is refracted towards the normalb) Is refracted away from the normalc) Is reflected along the same pathd) Does not get deviated8. A ray of light passes from a medium X to another medium Y. No refraction of light occurs if the ray of light hits the boundary of medium Y at an angle of:a) 120ob) 90oc) 45od) 0o9. A lens of focal length 12 cm forms an erect image, three times the size of the object. The distance between the object and image is:a) 8 cmb) 16 cmc) 24 cmd) 36 cm10.If an object is placed 21 cm from a converging lens, the image formed is slightly smaller than the object. If the object is placed at a distance of 19 cm from the lens, the image formed is slightly larger than the object. The approximate focal length of the lens is:a) 20 cmb) 18 cmc) 10 cmd) 5 cm​