Cathode rays are a stream of negatively charged particles or electrons in vacuum tubes. They were first seen by Johann Hittorf in 1869. They are named since they are emitted by electrode or cathode. In order to release the electrons, the electrons should first be detached from the atoms of the cathode.
Answer:
C. Carbon dioxide
Explanation:
Carbon dioxide is one of the end-product of combustion reactions involving many fuels today.
With the rapid increase in urbanization and technological development, man demand for energy increased tremendously. The discovery of fossil fuels paved the way for the astronomical increase in the concentration of carbon dioxide in the atmosphere. The burning of fossil fuels like coal and oil invovles the process where the carbon atoms present in these fuels combine with oxygen in the air to make CO2. This has resulted in an increase in the concentration of atmospheric carbon dioxide (CO2).
The burning fossil fuels for electricity, industry, heat, and transportation are the major sources of the emossion of carbon dioxide.
Also, the cutting down of trees for paper production, building construction and for the establishment of settlements also increase the concentration of carbon dioxide in the atmosphere. Trees are help remove carbon dioxide from the atmosphere through the process of photosynthesis. However, when these trees are cut down, carbon dioxide accumulates in the atmosphere.
Answer:
C) It will accelerate.
Explanation:
According to Newton’s second law of motion, when an object is acted on by an unbalanced force, it will accelerate.
An unbalanced force will change the speed or direction (or both) of an object. A change in speed and/or direction is acceleration.
A) is wrong. The object will stop moving only if there is a balanced force in the opposite direction.
B) is wrong. The object will decrease speed only if the unbalanced force has a component opposite to the direction of motion.
d) is wrong. The object will increase speed only if the unbalanced force has a component in the direction of motion.
Answer:
The correct option is;
c. the bone contains calcium salts, which are less reactive than the calcium ions found in the blood.
Explanation:
The most abundant metallic element found in the human body is calcium as it is present in the bones teeth and metabolism of the kidney
99 % of the calcium in the human body are found in the bones while the remaining 1 % circulates in the blood as ions
The bones of the vertebrate are made up of calcium salts such as calcium carbonate, calcium phosphate and calcium fluoride.
