Question

Give Reasons: a) Rubber band can be stretched still is a solid.
b) At 0 degree ice gives more cooling effect than water.
c) Explain the factor of evaporation.
d) Describe plasma and BEC.

Answer 1

a) A rubber band can be stretched still it's a solid because it's subset of solid.

We know that solids are rigid. Then how a rubber band can be stretched still it's considered as a solid?  

Rubber band are less rigid and they don't flow.. that's why they aren't considered as fluid..

rubber band can be stretched or I can change it's shape when force is applied but again it comes to is original shape when that force is removed. And if excessive force is applied, then it breaks.  

b) at 0° ice gives more cooling effect than water at the same temperature because of latent heat of fusion. Ice absorbs more heat when it melts than water. Therefore it's more effective in cooling as compared to water.  

c) factors of evaporation :-  
• increase in the surface area -   Evaporation is a surface phenomenon. When surface area is increased, then rate of evaporation also increases. That's why cloths dry up faster if we spread them out.  

• increase in temperature   As the temperature increases, rate of evaporation also increases. Because as we know that kinetic energy increases when the particles get heat. As a result, the particles will get enough energy to change in it's gaseous state.  

• decrease in humidity  Humidity means moisture (water) in air, and we know that air can hold a specific amount of water at a given temperature, so if there's humidity in air, then the rate of evaporation will be low. And if there's less humidity then rate of evaporation will be fast.  

d) plasma - we know that every connective tissue has it's matrix. blood has a fluid matrix which is known as plasma. Plasma contains red blood cells, white blood cells and platelets.  

HOPE THIS HELPS..!!