Science Exercise (Preparation Of Mid-term Exam Of Grade 2 Semester 2 Of Cambridge School)

Explanation
The Sun is the nearest star to the Earth. While the other options listed are also celestial bodies, the Sun is specifically classified as a star. It is the closest star to our planet and is essential for providing light, heat, and energy to sustain life on Earth.

Explanation
The moon reflects the sun's light.

Explanation
A bright glow from a lamp is caused by light. Light is a form of electromagnetic radiation that allows us to see. It is emitted by a light source such as a lamp.

Explanation
Darkness refers to the absence or very low levels of light. When there is little or no light, it is referred to as "dark." This is the opposite of brightness, which is associated with high levels of light. Darkness is commonly experienced during nighttime or in places where there is no source of light. It is a condition that limits visibility and makes it difficult to see or perceive objects.

Explanation
The given question asks for a light source, except for one option. Earth is not a light source, as it does not emit light on its own. Stars emit light, as they are massive balls of gas that produce energy through nuclear fusion. Torches are also light sources, as they produce light through the combustion of fuel. However, earth does not emit light and relies on external sources of light, such as the sun, for illumination.

Explanation
Fireflies are known for their ability to produce light through a process called bioluminescence. They have specialized cells in their abdomen that produce a chemical reaction, resulting in the emission of light. This adaptation helps them attract mates and communicate with each other in the dark. Fireflies are commonly seen flashing their lights during the night, making them the correct answer for an animal that can make light in the night.

Explanation
A light source that has batteries and a bulb is called a torch. It is portable and can be held using our hands. Torches are commonly used for providing light in dark areas or during power outages.

Explanation
When an object blocks the light, it creates a shadow. A shadow is a dark area that is formed on a surface when an object blocks the path of light. This occurs because the object prevents the light from reaching the surface behind it, resulting in a shadow being cast. Therefore, the correct answer is shadow.

Explanation
A cell is a device that can store electricity and is commonly referred to as a battery. It is a small electrochemical device that converts chemical energy into electrical energy. Cells are used in various electronic devices such as mobile phones, laptops, and remote controls to provide power for their operation.

Explanation
The correct answer is electricity because all the mentioned objects - lamp, computer, iron, and television - require electricity to function. They need an electrical power source to operate and perform their intended tasks. Without electricity, these objects would not be able to provide light, heat, or perform any electronic functions.

Explanation
A switch is a device that is used to control the flow of electricity by turning it on or off. It acts as a bridge between the power source and the electrical device, allowing the user to easily control the flow of electricity. By flipping the switch to the "on" position, the circuit is completed and electricity can flow, while flipping it to the "off" position breaks the circuit and stops the flow of electricity. Therefore, a switch is the correct answer for this question.

Explanation
Wire is commonly made from metal, such as copper, aluminum, or steel. These metals possess the necessary properties like conductivity, malleability, and tensile strength required for wires to transmit electricity or carry signals. Rubber and wood are not suitable materials for making wires as they lack the required conductivity and strength.

Explanation
The given correct answer is "conductor". A conductor is a material that allows electricity to pass through it easily. It has free electrons that can move freely within the material, allowing the flow of electric current. In contrast, an insulator does not allow the flow of electricity, while wood is a poor conductor of electricity.