Practice Questions On Measurement, Matter And Tissue For 7th Grade Students!

Air has larger intermolecular gaps compared to water, iron ball, and common salt. This is because air is a gas and its molecules are widely spaced, allowing for larger gaps between them. In contrast, water, iron ball, and common salt are in a liquid or solid state, where the molecules are more closely packed together, resulting in smaller intermolecular gaps.

This statement is false. Not all solids change directly into a liquid and then into a gas when heated. Some solids can undergo sublimation, which means they directly change from a solid to a gas without passing through the liquid state. Examples of substances that undergo sublimation include dry ice (solid carbon dioxide) and mothballs (naphthalene). Therefore, the statement that all solids first change to a liquid and then go to the gaseous state is incorrect.

A gas does not have a fixed shape or volume, and it can expand to fill any container it is placed in. Unlike liquids or solids, gases do not have a free surface because their particles are not held together by cohesive forces. Therefore, the statement "A gas has no free surface" is true.

Brownian motion refers to the random movement of particles suspended in a fluid due to the collisions with the fluid molecules. This motion is observed in fluids because the fluid molecules are constantly in motion and collide with the suspended particles, causing them to move randomly. Therefore, it is true that fluids perform Brownian motion.

Condensation refers to the process of water vapor changing into liquid water. This occurs when the temperature of the air is lowered, causing the water vapor molecules to lose energy and come together to form liquid droplets. This can be observed when warm air comes into contact with a cold surface, such as when water droplets form on the outside of a cold glass. Condensation is the opposite of evaporation, which is the process of liquid water changing into water vapor.

The given statement is true. It states that 1 gram per cubic centimeter (gm/cm^3) is equal to 1000 kilograms per cubic meter (kg/m^3). This conversion factor is commonly used in science and engineering to convert between different units of density.

The correct answer is kg/m^3. Density is defined as the mass per unit volume of a substance. The SI unit for mass is kilogram (kg) and the SI unit for volume is cubic meter (m^3). Therefore, the SI unit of density is kg/m^3.

Solids have the smallest intermolecular space compared to liquids and gases. In solids, the particles are closely packed together in a regular pattern, resulting in strong intermolecular forces. This close arrangement of particles limits the amount of space between them, leading to a smaller intermolecular space. In contrast, liquids and gases have more space between particles, allowing them to flow and occupy larger intermolecular spaces. Therefore, the statement that solids have the largest intermolecular space is false.

The correct answer is cubic meter. The cubic meter is the standard unit of volume in the International System of Units (SI). It is defined as the volume of a cube with sides of one meter in length. The cubic meter is commonly used for measuring large volumes, such as the volume of liquids, gases, or solids. It is a fundamental unit of measurement in physics, engineering, and other scientific fields.

Tendons actually connect muscles to bones, not muscles to muscles. Tendons are strong fibrous tissues that transmit the force generated by muscles to the bones, allowing movement to occur. This connection allows the muscles to pull on the bones, causing them to move and perform various actions.

A tissue is a group of cells that have similar structure and function. It is formed by cells of the same type that work together to perform a specific task. Therefore, a tissue is indeed formed of only one type of cells.

The density of air is given as 1.28 gm/litre. To convert this to gm/cm^3, we need to convert litres to cm^3. Since 1 litre is equal to 1000 cm^3, the density of air in gm/cm^3 will be 1.28 gm/1000 cm^3, which simplifies to 0.00128 gm/cm^3.

The conversion factor between kilometers per hour (km/h) and meters per second (m/s) is 1 m/s = 3.6 km/h. Therefore, to convert 36 km/h to m/s, we divide it by 3.6. 36 divided by 3.6 equals 10, so the answer is 10 m/s.

Blood and lymph are the correct options for the fluid connective tissue of humans. Blood is a specialized connective tissue that consists of red blood cells, white blood cells, and platelets suspended in a liquid called plasma. It transports oxygen, nutrients, hormones, and waste products throughout the body. Lymph, on the other hand, is a clear fluid that is derived from blood plasma and plays a vital role in the immune system by carrying white blood cells and removing waste from tissues. Both blood and lymph are essential for maintaining homeostasis and proper functioning of the body.

Parenchyma is a type of plant tissue that is composed of thin-walled cells. These cells are alive and have various functions such as storage, photosynthesis, and secretion. Collenchyma, on the other hand, is another type of plant tissue that provides support to growing parts of the plant. Collenchyma cells also have thin walls, but they are unevenly thickened and provide flexible support. Therefore, the correct answer is Collenchyma.

Collenchyma tissue is characterized by elongated and thickened cells at the corners. This tissue provides support and flexibility to growing plant parts, such as stems and leaves. The thickening of the cell walls in collenchyma tissue is due to the deposition of cellulose, hemicellulose, and pectin. This structural arrangement allows collenchyma cells to withstand mechanical stress and provide strength to the plant. Therefore, the given answer, "Collenchyma," is correct.

The area of a triangle is calculated by multiplying the base and height and dividing the result by 2. In this case, the base is 10cm and the height is 5cm. Therefore, the area of the triangle is (10cm * 5cm)/2 = 25 sq cm. To convert this to SI unit, we divide by 10000 since 1 sq m = 10000 sq cm. Thus, the area is 25 sq cm / 10000 = 0.0025 sq m.

Weight is not a scalar quantity because it has both magnitude and direction. Scalar quantities only have magnitude and no direction. Weight is a vector quantity because it depends on the force of gravity and is always directed towards the center of the Earth. Mass, speed, and area are all scalar quantities as they only have magnitude and no direction associated with them.