1.
Frequency is measured in...
Correct Answer
D. Hertz
Explanation
Frequency is measured in Hertz. Hertz is the unit of measurement for frequency and represents the number of cycles or oscillations of a wave that occur per second. It is commonly used to measure the frequency of sound waves, electromagnetic waves, and other periodic phenomena. Ampere, Metres, and Ohms are units of measurement for electric current, length, and electrical resistance respectively, and are not used to measure frequency.
2.
Sound cannot travel through...
Correct Answer
C. Vacuum
Explanation
Sound requires a medium to travel through, such as air, water, or solids. In a vacuum, there is an absence of any medium, so sound waves cannot propagate. Therefore, sound cannot travel through a vacuum.
3.
What is force divided by the of the point of application?
Correct Answer
B. Pressure
Explanation
Pressure is defined as force divided by the area of the point of application. It is a measure of the amount of force exerted on a given area. In this context, the question is asking for the term that represents force divided by the area of the point of application, which is pressure. Therefore, the correct answer is pressure.
4.
Why does a sharp knife cut so well?
Correct Answer
D. It has a small area so pressure is small
Explanation
A sharp knife cuts well because it has a small area, which results in a small amount of pressure being applied to the object being cut. When the pressure is small, the knife is able to easily penetrate the object, reducing resistance and allowing for a clean cut.
5.
What is normal in a ray diagram? It is the line drawn at angle _____ to the mirror surface.
Correct Answer
D. 90"
Explanation
In a ray diagram, the line drawn at a 90° angle to the mirror surface is considered normal. The normal line is an imaginary line that is perpendicular to the mirror surface at the point of incidence. It is used as a reference line to measure the angle of incidence and angle of reflection for the incident rays. The angle of incidence is the angle between the incident ray and the normal line, while the angle of reflection is the angle between the reflected ray and the normal line.
6.
Which of the following is the correct reason why we can see non-luminous objects?
Correct Answer
D. They reflect light into our eyes
Explanation
Non-luminous objects are visible because they reflect light into our eyes. Unlike luminous objects that emit their own light, non-luminous objects do not produce light on their own. Instead, they interact with light from external sources, such as the sun or artificial lights, and reflect some of that light back towards our eyes. This reflected light allows us to perceive the objects and see their color, shape, and texture.
7.
Which of the following is not true about light? Light is...
Correct Answer
B. Slower than sound
Explanation
Light is not slower than sound. In fact, light is the fastest known phenomenon in the universe. It travels at a speed of approximately 299,792 kilometers per second in a vacuum, which is significantly faster than the speed of sound. The speed of sound, on the other hand, varies depending on the medium it travels through, such as air, water, or solids. Therefore, the statement "Slower than sound" is not true about light.
8.
What is the difference between weight and mass?
Correct Answer
A. Mass is the quantity of substance while weight is a force
Explanation
Mass and weight are two different physical properties. Mass refers to the amount of matter in an object, while weight is the force exerted on an object due to gravity. Mass remains constant regardless of the location, while weight can vary depending on the strength of the gravitational pull. Therefore, the correct answer is that mass is the quantity of substance while weight is a force.
9.
The loss or gain of an electron in an atom result in the formation of...
Correct Answer
B. Ions
Explanation
When an atom gains or loses an electron, it becomes an ion. Ions are charged particles that have either a positive or negative charge. This occurs because the number of protons (positive charge) in the nucleus is no longer balanced by the number of electrons (negative charge) surrounding the atom. Therefore, the correct answer is ions.
10.
In an experiment, a stone and a feather are thrown from the same height. Neglecting air resistance, which will hit the ground first?
Correct Answer
C. Both will hit the ground the same time
Explanation
Both the stone and the feather will hit the ground at the same time. This is because neglecting air resistance, the only force acting on both objects is gravity. Gravity causes all objects to accelerate towards the ground at the same rate, regardless of their mass. Therefore, both the stone and the feather will experience the same acceleration and will reach the ground simultaneously.