Important Questions Test: Light, Shadows & Reflections - Class 6 MCQ

In a pinhole camera, the light rays pass through the small hole of the camera and incident on the white screen, kept on the other side of the source. This is possible because light travels in a straight line, which is known as the rectilinear propagation of light.

A body that allows almost all light to pass through it and doesn't reflect any light is called a transparent object. Transparent objects allow light waves to pass through them completely and unchanged, due to how the light interacts with the atoms in the object. Examples of transparent body are glass, sand timer, prism, fish tank, and camera lens.

If an incident light ray is reflected back along its original path by a plane mirror,then it means that the ray was incident normally on the plane mirror.And then its angle of incidence will be 0 degrees. Because the angle of incidence is the angle that an incident line or ray makes with perpendicular to the surface at the point of incidence.Here the incident ray is along the normal (perpendicular to mirror) so angle between incident ray and normal is zero.

• Objects which allow the light to pass through them completely without any obstruction are called  transparent objects.
• Objects which allow the light to pass through them partially are called translucent objects.
• Objects which do not allow the light to pass through them are called opaque objects.
• Since a diamond allows the light to pass through it completely   without any absorption or obstruction of light, it is a transparent object. 

Hence Option B correct

The shadow is formed when light falls at an angle to the stick and it is clear that light falling is completely parallel to stick B so stick B will form almost no shadow on ground.

Silvering is the chemical process of coating a non-conductive substrate such as glass with a reflective substance, to produce a mirror. While the metal is often silver, the term is used for the application of any reflective metal.

Among the options given:

1. A ball - This can form a circular shadow depending on the angle of the light source.
2. A flat disc - This will always form a circular shadow if the light source is perpendicular to the disc.
3. A shoe box - This typically forms a rectangular shadow due to its shape.
4. An ice cream cone - This would generally cast a shadow that is a truncated cone or irregular shape depending on the light source's angle.

The object that can never form a circular shadow is a shoe box

The correct answer is option (a) Sun. Shadow can be formed from other sources of light also, like, torch.

In a translucent object, the incident light gets partially transmitted through it. Thus, we can see the things through the translucent paper but they appear blurred. Therefore, the butter paper is definitely an example of the translucent objects.

Ground glass is a translucent body. The opacity of this body is in between the transparent and opaque bodies.

Formation of shadows is due to phenomena of rectilinear propagation of light . Shadows are created when an object, animal or person blocks out a portion of a light source. Shadows form in the opposite direction of whatever is blocking that source.

It is a transparent medium rest all are translucent

If we are able to see anything clearly through an object, then such an object is said to be a transparent object.
Translucent objects allow some light to travel through them. Materials like frosted glass and some plastics are called translucent. When light strikes translucent materials, only some of the light passes through them. The light does not pass directly through the materials.
An opaque object is something that allows no light through it. Concrete, wood, and metal are some examples of opaque materials. Some materials can be opaque to light, but not to other types of electromagnetic waves.

Shadow forms when light falls on a wooden block because wood is an example of an opaque object. Opaque objects do not allow light to pass through them. Shadows are formed when an opaque object comes in the path of light.

Transparent material allows light to pass through it and opaque object obstructs it.

Wool is a Opaque medium .

Light passes through the gaps present in between the leaves and produces bright spots.

The color of a shadow formed by red light is black if the object is completely opaque. 

Shadow is  formed when rays of light are stopped by an opaque object.

A pinhole camera is a simple camera without a lens but with a tiny aperture,(aperture is nothing but the hole here) a pinhole – effectively a light-proof box with a small hole in one side. Light from a scene passes through the aperture and projects an inverted image on the opposite side of the box.

A polished glass of red colour reflects most of the light incident on it so images of both persons are formed on it.

Tiny hole in a leaf is an example of natural pinhole camera.

• Diffraction is the phenomenon of bending of light waves around the corners of an obstacle or aperture, placed in the path of light beam. 
• Reflection is the phenomenon in which light rays on striking a polished surface(such as a mirror) bounce back or are sent back into the same medium. 
• Dispersion is the phenomenon of splitting of white light into its component colours (VIBGYOR) on passing through a glass prism.
• Refraction of light is the phenomenon of bending of light or change in the direction of light, when it passes obliquely from one transparent medium to another.

Hence, the correct answer is OPTION D. 

An object is defined as transparent when it allows all the rays striking on its surface to pass through it.