Question

34. What is the dioptrie power of a diverging lens if the rays travelling parallel to the principal axis of the lens seem (after the passage through the lens) to come from a point positioned in distance of -100 em from its centre? a)-10 D b)-1D )-0,01 D d)+0,01 D e)No answer is correct. 35. What is the colour representing the visible light with the lowest possible frequeney? a) green b) blue c) red d) violet e) No answer is correct. 36. Which of the phenomena is not caused by light interference? a) the varying (iridescent) rainbow colours of security holograms used to protect some trade marks b) the so-called Newton rings e) a colour spectrum seen on a screen behind an optical grating illuminated by polychromatic light d) red colour of the Sun just before the sunset e) No answer is correct.

Answer 1

  

almostequalto 3 times 10^3 K. �For a diverging lens, the focal length is f = -100 cm, = -1 m. �so, the power of the lens. �P = 1/f = 1/(-1) = -1 m^-1 = -10. �So, option (B) is correct. �In the visible spectrum of light VIBGYOR. �Wavelength(lambda) increases, from V rightarrow R. �frequency (f) decreases, from V rightarrow R. �so, lowest possible frequency, is Red option (c) is correct. �Red colour of the sun before the sunset occurs due to the scattering of light. (not interference). �So, option (D) is correct