A coil of wire of cross-section 0.75 square mm weighs 125g in air and 115g in water. What will be the length of the coil?
100000/75 cm
To find the length of the coil, we can use Archimedes' principle, which states that the buoyant force experienced by an object immersed in a fluid is equal to the weight of the fluid displaced by the object.
In this case, the difference in weight of the coil between air and water represents the weight of the fluid displaced by the coil.
The weight of the fluid displaced is given by the equation:
Weight of fluid = Weight in air - Weight in water
Here's how to calculate the weight of the fluid:
1. Convert the cross-sectional area of the coil to square meters:
Area = 0.75 square mm = 0.75 x 10^-6 square meters (since 1 mm = 10^-3 meters)
2. Calculate the volume of the fluid displaced:
Volume = Cross-sectional area x Length
3. Convert the weight of the coil in air and water to kilograms:
Weight in air = 125g = 125 x 10^-3 kg
Weight in water = 115g = 115 x 10^-3 kg
4. Determine the weight of the fluid displaced:
Weight of fluid = Weight in air - Weight in water
5. Determine the density of the fluid:
Density of water = 1000 kg/m^3 (for water at room temperature)
6. Use the equation: Density = Mass / Volume to find the volume of the fluid:
Volume = Weight of fluid / Density of water
7. Rearrange the equation from step 2 to solve for the length:
Length = Volume / Cross-sectional area
Plug in the values from the previous steps, and solve for the length of the coil.