GSEB Class 7 English How Things Work Solutions
Q: What type of mirror is typically used for car side mirrors?
Convex mirror.
Q: What type of image does a convex mirror produce?
An upright, diminished image.
What is the advantage of using a convex mirror on a car?
It provides a wider field of view.
What is the characteristic of the image produced by a convex mirror?
It is always virtual, diminished, and erect.
Q: What happens to the size of the image produced by a convex mirror as an object gets closer to the mirror?
The image gets larger until it reaches approximately the size of the object when it touches the mirror.
Activity 4
Q: What makes stars and fireflies shine with their own light?
They produce their own light.
Q: What happens when photons of light hit most things?
They bounce back.
Q: What happens when photons hit a hard and smooth surface?
All the photons bounce back and the surface looks like a plane.
Q: What happens when photons hit a soft and rough surface, such as a blanket?
The photons bounce back at different angles.
Q: How do we see the shape of things?
When the bouncing photons enter our eyes.
Q: What do bouncing photons show?
The shape of the things they hit.
Activity 5
Q: What is visible light?
It is electromagnetic radiation that is visible to the human eye and responsible for the sense of sight.
Q: What is the wavelength range of visible light?
It ranges from about 389 nanometers to about 749 nanometers.
Q: What are the primary properties of visible light?
Intensity, propagation direction, frequency or wavelength, spectrum, and polarization.
Q: What is the speed of visible light in a vacuum?
299,792,458 meters per second, which is one of the fundamental constants of nature.
Q: What are photons?
They are tiny packets in which visible light, as well as all types of electromagnetic radiation, are emitted and absorbed.
Q: What is the wave-particle duality of visible light?
Visible light exhibits properties of both waves and particles.
Q: What is optics?
It is the study of light, which is an important research area in modern physics.
Q: What is the primary source of light on Earth?
The sun, which emits about 44% of the electromagnetic radiation that reaches the ground in the visible light range.
