Science 3 Marks Question

When white light is reflected from the surface of a Compact Disc (CD), many colours are seen. When we blow soap bubbles, they appear colourful. The disc painted with seven colours of the spectrum is called Newton's disc.


David spins a multicoloured wheel rapidly.
(i) What colour will the rapidly spinning wheel appear to be?
(ii) What acts like a prism in the formation of a rainbow in nature?
(iii) What happen when we pass a red laser light through the prism?

State the correct sequence (1-7) of colours in the spectrum formed by the prisms A and B shown in the figure.

Label A denotes the lens used in microscope to see objects. Which type of lenses are used in the microscope which helps to see the microbes?

A student is asked to focus sunlight using two different lenses onto a paper.


Observe the image carefully and answer the following questions.
(i) State the name for the shape of lenses X and Y.
(ii) Which of these two lenses can be used to magnify images?
(iii) Explain the changes that happen to the paper kept under both the lenses.

Last Sunday Girish's mother, Priyanka was preparing the dinner in her kitchen for Girish and his father. Both of them were feeling so much hungry and they sat ideally on their respective chairs and having empty plates and spoons on their dinning table. They were shouting like a 5 years old child that they wanted the dinner so eagerly to fulfil their stomach. After sometime, Girish's mother served the cooked food to both of them and when Girish was just about to eat the rice with the help of spoon, he noticed that the spoon has such a shining surface that it reflected the light rays incident on it.
(i) Explain the importance of shining surface in the reflection of light.
(ii) Name the type of spherical mirror represented by the shining steel spoon.
(iii) Mention the values shown by Priyanka here towards her family

Assume, a person is standing in front of a plane mirror. The distance between the mirror and his image is 6m. If the person moves 2 m towards the plane mirror, what would be the distance between the person and his image?

One day, Ramesh's friends were performing their respective experiments given by their teacher. While sitting in the practical lab instead of performing experiment, Ramesh was playing with his meter scale. All of the sudden, he held the scale in his hand and started moving in front of tubelight, then he observed the seven colours of white light. After sometimes, he got scolded by his lab teacher for not performing the experiment.
(i) Give the name of phenomenon that leads to the formation of band of seven colours.
(ii) Name the constituent colours of white light.
(iii) Mention the values shown by Ramesh here.