Physics 2000 JAMB Past Questions - Question 25: A quantity of water at 0°C is heated to about 30°C. At each degree rise in temperature, its density will

Correct Answer

B

Explanation

The density of water changes with temperature. At 0°C (the freezing point of water), water is at its maximum density, and as it is heated, its density decreases.

As water is heated from 0°C to 4°C, it becomes less dense, and its volume increases. However, at temperatures above 4°C, as water continues to heat, it starts to become denser again. This is because water has a unique property where its density decreases as it cools from 4°C to 0°C, but then it starts to increase as it cools below 0°C (as it freezes into ice).

So, when you heat water from 0°C to 30°C, its density will not consistently decrease with each degree rise in temperature. It will decrease from 0°C to 4°C and then start to increase as you go beyond 4°C. At 30°C, the density of water will be less than at 0°C but more than at 4°C.

In summary, the density of water does not linearly decrease with each degree rise in temperature from 0°C to 30°C; it follows a more complex pattern due to its unique thermal properties.  
decrease.

As water is heated from 0°C to 30°C, its density will decrease. This is because water exhibits a maximum density at approximately 4°C. As the temperature of water increases from 0°C, its density decreases until it reaches this maximum density point. Beyond this point, as the temperature continues to rise, the density of water decreases further.

The decrease in density with increasing temperature is due to the thermal expansion of water. When water is heated, the average kinetic energy of its molecules increases, causing them to move more vigorously and occupy more space. This expansion leads to a decrease in the density of water.

Therefore, at each degree rise in temperature, the density of water will decrease.