Light - Part 1 | Assessment | English | Grade 8

Moon is visible because _____ .

• it illuminates its own light

• it reflects light from the Earth

• it reflect light from the Sun

• none of the above

Answer explanation

Moon does not emit its own light, it reflects the light from the Sun. Sun is the only star in our solar system that generates its own light, all the other planets, asteroids, etc, reflect this light from the sun.

Objects that do not produce their own light are called _____ .

• non-luminous object

• luminous objects

Answer explanation

Objects that do not generate their own light are called non-luminous objects, whereas objects that do generate their own light are called luminous objects.

Reflection can occur on _______ .

• rough surfaces

• smooth surfaces

• all surfaces

• no surface

Answer explanation

Reflection occurs on all surfaces, this is why we can see objects. Some surfaces that are smooth reflects the light coherently, like a mirror.

The angle of incidence and the angle of reflection are ________ .

• never equal

• always equal

• sometimes equal

• none of the above

Answer explanation

The first rule of reflection says that the angle of incidence and the angle of reflection are always the same.

The speed of light is approximately _________ in air.

• 300 m/s

• 3,00,000 m/s

• 30,00,00,000 m/s

• None of the above

Answer explanation

The speed of light is measured to be 30,00,00,000 m/s or 3,00,000 Km/s.