Light Shadows And Reflection Test - 1

Rectilinear propagation of light means that light travels in a straight line in a homogeneous medium.

A tube light is a cold source of light. In a cold source of light, first electricity initiates a chemical reaction and then chemical energy is converted into light energy. In a hot source of light, electrical energy is converted into heat energy and then heat energy is converted into light energy.

Both statements A and B are correct.

We can see an object if it reflects the light and hence, we can say that if there is no light, we cannot see the object.

Light always travels in a straight line, that is why we cannot see the objects through a T-shaped pipe.

For the formation of a shadow, there should be a source and a screen, and also the object must be placed in between the source and the screen.

A shadow moves on the screen whenever the source or the object moves parallel to the screen. When the source moves away from the screen, the size of the shadow changes but position of the shadow remains unchanged. Colour of the light does not affect the size and movement of the shadow.

Pinhole camera produces real, inverted and diminished image; so statements (a) and (b) are incorrect.

All the given statements are correct about a pinhole camera.

1.The circular patches of light formed on the ground are kind of images.
2.The circular patches are pinhole images of the Sun.
3.We see circular images of the Sun irrespective of the irregular shapes of the gaps between the leaves.

Angle of incidence, i = 90° - 20° = 70°
Now, we know:
Angle of incidence = Angle of reflection
Hence, angle of reflection = 70°

As the object distance and the image distance are the same, therefore the distance between John and his image is 6 m.

A plane mirror always forms an imaginary and erect image, and the distance of the image from the mirror is always equal to the distance of the object from the mirror.