KBC Questions and Quiz, Multiple Choice Questions and Answers
Displaying 591 to 600 of 2066 Questions. You are on Page No. 60 of total 207 pages
Question: What the main particles of an atom are?
Incorrect Answer
Correct Answer The proton has a postive charge, the neutron has no charge, and the electron has a negative charge. The electrons are on the outer orbit of a atom. A covalent bond exists when electrons are shared between atoms. This is the most common form of chemical bonding. All matter is made out of atoms. Chemical elements contain only one type of atom. All the chemicals in a cell are made out of atoms, so atoms must be VERY, VERY tiny indeed!
Question: What gas plants contribute to the earth's atmosphere?
Incorrect Answer
Correct Answer Plants keep the oxygen content stable by photosynthesis. They release oxygen gas into the atmosphere as a by-product of photosynthesis. Denitrifying bacteria contribute to the vast amount of atmospheric nitrogen in the atmosphere (78% of the earth's atmostphere is nitrogen). Carbon dioxide is needed for photosynthesis, but isn't released into the atmosphere by photosynthetic processes.
Question: What organelle is known as the 'brain' of the cell?
Incorrect Answer
Correct Answer The nucleus controls all the reactions within the cell. The chloroplast is the organelle in plant cells where photosynthesis (where radiant energy from the sun is converted to chemical energy) takes place. It contains pigments known as chlorophyll. Chloroplasts are only found in plant cells. The mitochondria is where respiration occurs. All cells (not just plant cells) contain mitochondria. All cells also have a cell-membrane. This selectively allows some materials to pass, and not others, such as starches.
Question: What two elements common table salt is made out of?
Incorrect Answer
Correct Answer Table salt (sodium chloride) is made out of the elements sodium and chlorine. It is made up of one atom of each. Its chemical formula is NaCl. A little salt is needed for all human beings, but too much salt can lead to problems, like high-blood pressure.
Question: A _______ beam is one whose rays remain the same distance apart.
Incorrect Answer
Correct Answer A parallel beam is one in which the light rays always remain the same distance apart. A convergent beam is one in which the light rays slowly converge (come close together and finally meet) as the beam progresses. A divergent beam is one in which the light rays slowly diverge (go far apart) as the beam progresses.
Question: Non-luminous bodies become visible when they _______ light into our eyes.
Incorrect Answer
Correct Answer Bodies like the moon and planets do not radiate their own light and they become visible only when they reflect another source of light into our eyes. These bodies are called non-luminous bodies.
Question: Materials through which light cannot pass are said to be...?
Incorrect Answer
Correct Answer Opaque materials are those which do not allow the rays of light to pass through them at all. Hence, objects cannot be seen through opaque materials such as wood and metal.
Question: The distance between one of the magnetic poles and the centre of the bar magnet is called the...?
Incorrect Answer
Correct Answer The length of magnet is the distance between one of the magnetic poles (north or south) and the centre of the magnet (ON = OS = L). On the other hand, the effective length is the distance between the magnetic north pole and the magnetic south pole of a bar magnet (NS = 2L). Thus, the effective length is twice the length of magnet.
Question: The distance between the magnetic north pole and magnetic south pole of a bar magnet is called the...?
Incorrect Answer
Correct Answer The distance between the magnetic north pole and the magnetic south pole of a bar magnet is the effective length (NS = 2L), whereas the distance between one of the magnetic poles (north or south) and the centre of the magnet is called the length of magnet (ON = OS = L). Thus, the effective length is twice the length of magnet.
