Questions

Pericles

Can’t delete a row from primary table if there are related rows in secondary table.

Covalent bonds hold atoms together because the attraction between the positively charged nuclei and the negatively charged shared electrons is greater than the repulsions between the nuclei themselves.

Pressure is Not a form of Energy.

Energy : It is defined as the ability to do work.

Energy comes in two basic forms. They are :

1. Potential Energy

2. Kinetic Energy

Potential Energy is any type of stored energy. It can be chemical, nuclear, gravitational, or mechanical.

Kinetic Energy is found in movement. An airplane flying or a meteor plummeting each have kinetic energy. Even the tiniest things have kinetic energy, like atoms vibrating when they are hot or when they transmit sound waves. Electricity is the kinetic energy of flowing electrons between atoms.

Radio waves have much longer wavelengths and lower frequencies than do visible light waves. In contrast, X-rays have much shorter wavelengths and higher frequencies. 

Ultraviolet Light (UV). part of the electromagnetic spectrum that consists of waves with frequencies higher than those of visible light and lower than those of x-rays.

Database provides necessary means to achieve this abstraction. By structure of a database we mean the data types, relations, and constraints that should hold on the data.