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Light Worksheet-7

Light Worksheet-7

 

  1. Define dispersion of light.

 

  1. Name the colours in the order they appear in the spectrum of light.

 

  1. What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?

 

  1. What are the two factors responsible for an object to be seen?

 

  1. What is meant by normal?

 

  1. Define the angle of incidence.

 

  1. What name is given to the angle between the normal and the reflected ray?

 

  1. When the reflected rays are parallel, what type of reflection is taking place?

 

  1. In irregular reflection, are the reflected rays parallel or not?

 

  1. What are luminous objects?

 

  1. What are illuminated objects?

 

  1. Name the device which uses the principle of multiple images.

 

  1. What is white light?

 

  1. Give one example of natural dispersion.

 

  1. What is the function of cornea?

 

  1. What type of lens is present in the eye?

 

  1. For how long does the image of an object persist on the retina?

 

  1. What is meant by accommodation?

 

  1. What is the minimum distance at which an eye can see?

 

  1. Which vitamin is responsible for eye defects?

 

Answer:

  1. Splitting up of white light into seven colours when it passes through a glass prism is known as dispersion of light.

 

  1. VIBGYOR - Violet, Indigo, Blue, Green, Yellow, Orange and Red.

 

  1. The angle of incidence = 45°

 

  1. The sense of vision and light are required.

 

  1. The perpendicular drawn at the point of incidence is known as normal.

 

  1. The angle between the incident ray and the normal is known as angle of incidence.

 

  1. Angle of reflection.

 

  1. Regular reflection

 

  1. In irregular reflection the reflected rays are not parallel.

 

  1. The objects which give their own light are known as luminous objects e.g., sun.

 

  1. Objects which reflect the light falling on them and can be seen are known as illuminated objects.

 

  1. Kaleidoscope.

 

  1. Sunlight is a mixture of seven colours and it is also known as white light.

 

  1. Formation of rainbow.

 

  1. Cornea protects the interior of the eye from any damage.

 

  1. Convex lens

 

  1. The image of an object persists for 1/16th of a second.

 

  1. The eyes can see nearby and far-off objects clearly by changing the thickness of the eye lens. This is known as accommodation.

 

  1. 25 cm

 

  1. Vitamin A