Ions are particles formed when an atom of an element looses or gains electrons to attain a stable configuration.They are either positively charged (cations) or negatively charged (anions). Ionic crystals consists of ions bound together by electrostatic attraction forming a regular arrangement, geometric structure called crystal lattice. In an ionic solid the ions are held by strong attractive forces (tightly bound) and cannot move from their positions in the crystal structure and therefore, do not conduct electricity.
Pacemaker........................................................
Answer:
See the explanation below
Explanation:
Student c's belief is fulfilled only for the movement of the earth with respect to the sun. But it has no validity or does not exist when it is necessary to explain other physical phenomena with respect to other satellites. For example, how would you explain the phases of the moon, if the Earth is located in the center of the Galaxy?, another serious question regarding the observations made by scientists millions of years ago, where they observed that the distances of the Earth from other planets were changing, with respect to time. If the Earth was in the center, all the planets and the sun would revolve around it preserving a constant distance (radius), at all times.
Other phenomena to explain would be the seasons on Earth, these are due to the axis of inclination of the Earth and the rotation of it around the sun.
Velocity of an object is given as
now we have
time = 3 hours
now from above formula
so its velocity is 40 mph and its a vector quantity whose direction is towards NORTH
correct answer is B
