For a particular multi-electron atom, application of the variational approach using an effective nuclear charge parameter Z 0 results in the following expression for E(Z 0 ), where a is a constant and energy is in atomic units (Hartree): E(Z 0 ) = −Z 0 e −aZ0 Determine the variational parameter Z 0 and the (minimum) variational energy.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

compass can be used day and night, cloudy or sunny

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.

gravitational energy

electrical energy

kinetic energy

ligh energy