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 principle axis after refraction.
(b) Name the invisible radiations which can be obtained using quartz prism? State one use of these radiations.
(c) Name one radiations having wavelength longer than the wavelength of these radiations.
Answer
(a) The ray will pass through different points on principle axis after refraction through the convex lens. Red colour will deviate the least, followed by green and then blue will deviate the most.
(b) Ultraviolet radiations. Ultraviolet radiations are used for sterilising air, surgical equipment, etc.
(c) Infrared radiation.
Related Questions
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?
Sumit and Sachin went for a trek and during the journey they visited a cottage. They suspended their bags to the two ropes hanging from P and Q on a wheel capable of rotating around O. Sumit suspended his bag to the rope Q and Sachin suspended his bag from the rope P. The wheel remained in equilibrium.
(a) State with a reason who is carrying a heavier bag.
(b) Based on the principle of moments, write a mathematical relation that can be used to determine the weight (W) of Sachin's bag, given that the weight of Sumit's bag is 18 kgf.
The diagram below shows a block and tackle system.
(a) Copy and complete the labelled diagram showing the correct connection of the tackle, the direction of the forces involved to obtain maximum V.R. with the convenient direction.
(b) Calculate the M.A. of this pulley system if its efficiency is 80%.