Physics 2010 JAMB Past Questions - Question 17: The density of a certain oil on frying becomes 0.4 kg^-³ with a volume of 20m³.What will be its initial volume when its initial density is 0.8kgm^-³assuming no loss of oil due to spillage ?

Correct Answer

A

Explanation

Mass = D X V = 0.4 x 20 = 8kgTherefore M/D = 8/0.8 = 10m³
To find the initial volume of the oil when its initial density is 0.8 kg/m³, you can use the formula for density:

Density = Mass / Volume

Let's assume the initial volume of the oil is Vâ‚€, the initial density is ρâ‚€, and the final density is ρâ‚�. We know that no oil is lost, so the mass remains constant:

Mass₀ = Mass�

The mass of the oil is given by:

Mass = Density * Volume

So, for the initial state:

Massâ‚€ = ρâ‚€ * Vâ‚€

And for the final state:

Massâ‚� = ρâ‚� * 20 m³

Since the mass remains the same, we can equate the two expressions for mass:

ρâ‚€ * Vâ‚€ = ρâ‚� * 20 m³

Now, we can solve for the initial volume (Vâ‚€):

Vâ‚€ = (ρâ‚� * 20 m³) / ρâ‚€

Plugging in the values:

ρâ‚€ = 0.8 kg/m³
ρâ‚� = 0.4 kg/m³
Volume after frying (Vâ‚�) = 20 m³

Vâ‚€ = (0.4 kg/m³ * 20 m³) / 0.8 kg/m³

Vâ‚€ = (8 kg) / (0.8 kg/m³)

Vâ‚€ = 10 m³

So, the initial volume of the oil, assuming no loss of oil due to spillage, is 10 cubic meters.