Physics
(a) Mixture of red + blue + green is passed through a convex lens as shown in the diagram below. State whether the ray passes through a single point or through different points on the principal axis after refraction.
(b) Name the invisible radiations which are studied using the quartz prism.
(c) State one use of these radiations.
(d) Name one radiation having the wavelength longer than the wavelength of these radiations.
Answer
(a) The ray will pass through different points on principal axis after refraction through the convex lens as the refractive index of a medium decreases with the increase in wavelength so red colour will deviate the least, followed by green and then blue will deviate the most.
(b) Ultraviolet radiations.
(c) Ultraviolet radiations are used for sterilizing air, surgical equipment, etc.
(d) Infrared radiation.
Related Questions
The diagram below shows a fish in the tank and its image seen in the surface of water.
(a) Name the phenomenon responsible for the formation of this image.
(b) A double convex lens with refractive index μ1 inside two liquids of refractive indices μ2 and μ3 are shown in the diagrams below. The refractive indices are such that μ2 > μ1 and μ1 > μ3
How would a parallel incident beam of light refract when it comes out of the lens in each of the cases shown above?
(1) in figure a.
(2) in figure b.
The refractive index of water is 1.33 at a certain temperature. When the temperature of water is increased by 40°C, the refractive index changes to 'x'.
(a) State whether x < 1.33 or x > 1.33.
(b) State two differences between normal reflection and total internal reflection.
An object is placed at a distance 24 cm in front of a convex lens of focal length 8 cm.
(a) What is the nature of the image so formed?
(b) Calculate the distance of the image from the lens.
When sunlight passes through water droplets in the atmosphere it gets dispersed into its constituent colours forming a rainbow. A similar phenomenon is observed when white light passes through a prism.
(a) Which colour will show the maximum angle of deviation and which colour will show the minimum angle of deviation?
(b) If Instead of sunlight, a green-coloured ray is passed through a glass prism. What will be the colour of the emergent ray?