1. Light travels ______ km per second in air or vacuum. 2. Materials that allow light to pass through completely are known as ______

Question

Fill in the Blanks.

1. Light travels ______ km per second in air or vacuum. 

2. Materials that allow light to pass through completely are known as ______ material.

3. Materials that allow light to pass through partially are called ______ materials.

4. Materials that are not able to allow light to pass through it are called ______ materials.

5. ______ is always against, opposite side of light source.

Answer 1

1. 3 lakh 

2.  transparent

3. translucent 

4. opaque 

5. Shadow