7. Total internal reflection has important applications in fibre optic surgery. A long, narrow glass optical fibre is used in microsurgery for lessening trauma and the chance of infection, and for reducing the healing period. Light within an optical fibre undergoes total internal reflection hundreds of thousands of times without escaping. The critical angle at the glass-air interface (nglass = 1.55) is A. 40.20 B. 56.30 C. 33.70 D. 49.8 8. If a 3.00 cm tall object is placed 15.0 cm in front of a concave mirror with a centre of curvature of 25.0 cm, then the height of the image is A. 0.600 cm Pile oldjob s dy B. 7.50 cm C. 1.88 cm . 15.0 cm of mis mouf ingil to nodestell a 9. A student uses an optical bench and places a burning candle with a 1.00 cm high flame at a distance of 20.0 cm from a convex mirror with a focal length of 15.0 cm. The image is Isedo A. virtual, erect, and larger. B. real, erect, and larger. C. virtual, erect, and smaller. . real, inverted, and smaller. gro odi bald 10. A 5.00 cm tall object is placed 10.0 cm from a diverging lens. The image is one-fifth the size of the object. The magnitude of the focal length of the lens is: A. 1.67 cm B. 0.400 cm C. 0.600 cm D. 2.50 cm 11. White light is shone through a diffraction grating producing a spectrum of colors. Which color o the spectrum produces its first maximum at the greatest angle? A. Red B. Green C. Violet D. Yellow