Name the units used to measure the distance between celestial objects.
The units used to measure the distance between celestial objects include astronomical units (AU) and light years (ly).
What is the density of gold?
The density of gold is approximately 19,320 kilograms per cubic meter (kg/m^3).
[IX] Answer briefly.
What are derived quantities?
Derived quantities are physical quantities obtained by combining fundamental quantities mathematically. Examples include area, volume, and density.
Distinguish between the volume of liquid and capacity of a container.
The volume of a liquid refers to the amount of space it occupies, while the capacity of a container is the maximum volume of liquid or substance it can hold.
Define the density of objects.
Density of objects is the mass of a substance per unit volume. It indicates how much mass is packed into a given volume and is often expressed in kilograms per cubic meter (kg/m³).
What is one light year?
One light year is the distance that light travels in vacuum over the span of one year. It is approximately equal to 9.46 trillion kilometers.
Define – Astronomical unit.
An astronomical unit (AU) is the average distance between the Earth and the Sun, which is approximately 149.6 million kilometers. It’s used as a unit of measurement in astronomy to express distances within the solar system.
[X] Answer in detail
Describe the graphical method to find the area of an irregularly shaped plane figure.
Do it on your own
How will you determine the density of a stone using a measuring jar?
To determine the density of a stone using a measuring jar, you can follow the displacement method. First, fill the measuring jar with a known volume of water and record the initial volume reading. Then, carefully lower the stone into the water, ensuring it is fully submerged. Measure and record the new volume reading, which will be greater than the initial volume due to the displacement of water by the stone. The difference between the final and initial volume readings represents the volume of water displaced by the stone. Since density equals mass divided by volume, you can calculate the density of the stone by dividing its mass by the volume of water displaced.
[XII] Numerical problems:
A circular disc has a radius 10 cm. Find the area of the disc in m2 (Use π = 3.14).
- Area of the circular disc =π×radius2=π×radius2
- Given: radius (rr) = 10 cm
- Area =3.14×102=3.14×102 =314 cm2=314 cm2
- Converting to square meters: 314 cm2314 cm2 =0.0314 m2=0.0314 m2
The dimension of a school playground is 800 m × 500 m. Find the area of the ground.
- Area of the school playground =length×width=length×width
- Given: Length = 800 m, Width = 500 m
- Area =800×500=800×500 =400,000 m2=400,000 m2
Two spheres of same size are made from copper and iron respectively. Find the ratio between their masses (Density of copper is 8,900 kg/m3 and iron is 7,800 kg/m3).
- Ratio of masses of spheres made from copper and iron respectively:
- Given: Density of copper (DcopperDcopper​) = 8,900 kg/m³, Density of iron (DironDiron​) = 7,800 kg/m³
- As the size of the spheres is the same, the ratio of their masses will be the same as the ratio of their densities.
- Ratio of masses =DcopperDiron=8900/7800=89/78
A liquid having a mass of 250 g fills a space of 1000 cc. Find the density of the liquid.
- Density of the liquid =MassVolume=VolumeMass​
- Given: Mass = 250 g, Volume = 1000 cc
- Density =250 g1000 cc=1000 cc250 g​ =0.25 g/cc=0.25 g/cc
A sphere of radius 1cm is made from silver. If the mass of the sphere is 33g, find the density of silver (Take π = 3.14).
- Density of silver =MassVolume=VolumeMass​
- Given: Mass = 33 g, Radius = 1 cm
- Volume of sphere =43πr3=34​πr3
- =43×3.14×(1)3=34​×3.14×(1)3 =4.186 cm3=4.186 cm3
- Density =33 g4.186 cm3=4.186 cm333 g​ =7.88 g/cm3=7.88 g/cm3
