Question

D. Short question answer :-
1. Calculate the pressure exerted by a sail on water if the force applied by the sail is
50,000 N and the surface area of the sail is 250 m2.
2. What is an ignition temperature ?
3. Sodium and potassium are stored in kerosene. Why?
4. Name & define the process responsible for the growth of an organism ?​

Answer 1

Answer:

2)The autoignition temperature or kindling point of a substance is the lowest temperature in which it spontaneously ignites in normal atmosphere without an external source of ignition, such as a flame or spark. ... The ignition temperature of a substance is the least temperature at which the substance starts combustion.

3)Sodium and Potassium are highly reactive metals and react vigorously with the oxygen, carbon dioxide and moisture present in the air such that it may even cause a fire. To prevent this explosive reaction, Sodium is kept immersed in kerosene because Sodium doesn't react with kerosene.

4)The increase in size and changes in shape of a developing organism depend on the increase in the number and size of cells that make up the individual. Increase in cell number occurs by a precise cellular reproductive mechanism called mitosis. Mitosis is the process responsible for the growth of an organism.

Answer 2

Explanation:

1)pressure=force/area

=50,000N/250m^2

=200 Nm^2

2)The temperature at which a substance burns is called its ignition temperature.

3)because they are highly reactive to oxygen present in the air.They are highly inflammable.so, they are kept in kerosene.

4)Life processes

definitoin-The basic functions performed by living orgainisms to maintain their life on this Earth are called life processes.

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