1.
Which of these are the primary colours?
Correct Answer
C. Red, Yellow, Blue
Explanation
The primary colors are the three colors that cannot be created by mixing other colors together. They are the fundamental colors that can be combined to create all other colors. In this case, the correct answer is red, yellow, and blue. These three colors are considered primary because they cannot be formed by mixing any other colors together.
2.
Which of the following is not a rule about light?
Correct Answer
B. It can pass through opaque objects
Explanation
The correct answer is "It can pass through opaque objects." This statement is not a rule about light because opaque objects do not allow light to pass through them. Opaque objects block or absorb light, preventing it from passing through and causing the objects to appear solid or non-transparent.
3.
Look at the diagram below.
Which structure helps focus the light on to the retina?
Correct Answer
D. The lens
Explanation
The lens helps focus the light onto the retina. The lens is a transparent structure located behind the iris and the pupil in the eye. It has the ability to change its shape, allowing it to adjust the focus of light onto the retina. This process is known as accommodation and it ensures that the light rays converge onto a single point on the retina, resulting in clear and sharp vision.
4.
The pupil is made up of coloured muscle.
Correct Answer
B. False
Explanation
The pupil is not made up of colored muscle. The pupil is actually a hole in the center of the iris, which is the colored part of the eye. The iris contains muscles that control the size of the pupil and regulate the amount of light that enters the eye. Therefore, the statement that the pupil is made up of colored muscle is incorrect.
5.
Light travels in a...
Correct Answer
B. Straight line
Explanation
Light travels in a straight line because it is an electromagnetic wave that propagates in a vacuum or a transparent medium. It follows the principle of rectilinear propagation, where it moves in a straight path from its source until it encounters an obstacle or changes medium. This behavior is explained by the wave nature of light and the fact that it travels at a constant speed in a uniform medium. The straight-line path of light allows for predictable and accurate predictions in optics and the study of light.
6.
The inventor of an electric light bulb was?
Correct Answer
A. Thomas Alva Edison
Explanation
Thomas Alva Edison is credited with inventing the electric light bulb. He developed and improved upon previous designs, eventually creating a practical and commercially viable version of the light bulb. Edison's invention revolutionized the way people lived and worked, providing a safe and reliable source of artificial light. His contributions to the field of electricity and lighting technology have had a lasting impact on society.
7.
Which of these objects is transparent?
Correct Answer
C. Car windscreen
Explanation
The correct answer is car windscreen. A car windscreen is transparent, meaning that light can pass through it easily, allowing us to see through it clearly. Wood, frosted glass window, and paper bag are not transparent as they either block or scatter light, making it difficult to see through them.
8.
Which of these objects is translucent?
Correct Answer
C. Frosted glass window
Explanation
A translucent object allows some light to pass through, but scatters it in different directions. A solid wooden door is opaque, meaning it does not allow any light to pass through. A car windscreen is transparent, allowing light to pass through without scattering it. However, a frosted glass window is translucent because it allows some light to pass through, but scatters it due to its textured surface. A brick wall is also opaque, not allowing any light to pass through. Therefore, the correct answer is the frosted glass window.
9.
Which of these objects are opaque?
Correct Answer
A. Brick wall
Explanation
A brick wall is considered opaque because it does not allow light to pass through it. It is a solid object that blocks the passage of light, making it impossible to see through. Unlike a car windscreen, white plastic bag, or a goldfish bowl, which are transparent or translucent to some extent, a brick wall is completely solid and does not allow any light to pass through it.
10.
What is the approximate speed of light?
Correct Answer
C. 300,000 kilometres per second
Explanation
The approximate speed of light is 300,000 kilometers per second. This is a well-known scientific fact and is widely accepted. The speed of light is incredibly fast, and it is a fundamental constant in physics. It plays a crucial role in many scientific theories and has been measured and confirmed through various experiments and observations.