Liquids and gases never show
- A.diamagnetic property
- B.paramagnetic property
- C.ferromagnetic property
- D.electromagnetic property
Correct answer
Explanation
The correct answer is C, ferromagnetic property. Ferromagnetism needs the atomic magnets of a substance to line up together in fixed regions called domains, and this happens only in the ordered structure of a solid.
In iron, cobalt, nickel and some alloys, neighbouring atoms keep their magnetic moments aligned over large domains, so the material is strongly attracted by a magnet and can itself become a permanent magnet. In a liquid or a gas the atoms move about freely and their thermal motion destroys any such long-range order. Even iron loses its ferromagnetism when heated above its Curie temperature of about 770 °C, well before it melts.
A is wrong because diamagnetism, a weak repulsion by a magnet, is shown by water, nitrogen gas and many other liquids and gases. B is wrong because paramagnetism, a weak attraction, is shown by liquid and gaseous oxygen. D is wrong because 'electromagnetic' describes the link between electricity and magnetism, not a class of magnetic material that fluids lack.
Exam tip: liquid oxygen is paramagnetic, water is diamagnetic, and only solids below the Curie point are ferromagnetic.
Practice Questions
View allOsmosis is the process of movement of water molecules from its
- A.higher concentration to its lower concentration through a cell wall.
- B.lower concentration to its higher concentration through a fully permeable membrane.
- C.higher concentration to its lower concentration through a fully permeable membrane.
- D.higher concentration to its lower concentration through a semi-permeable membrane.
Show answer
Osmosis is the passage of water from where water is more concentrated (a dilute solution) to where it is less concentrated, across a membrane that lets water through but holds back solutes.
Read the full explanation →The chemical properties of an element depend upon
- A.the number of isotopes of the element
- B.the mass number of the element
- C.the total number of neutrons in the element
- D.the number of electrons in the outermost shell of the element
Show answer
Chemical reactions involve only the outer, or valence, electrons, so these decide how an element behaves. Atoms combine by losing, gaining or sharing their valence electrons to reach a stable arrangement, usually eight electrons in the outer shell.
Read the full explanation →Which one of the following is not found in animal cells ?
- A.Free ribosomes
- B.Mitochondria
- C.Nucleolus
- D.Cell wall
Show answer
Animal cells are bounded only by a flexible plasma membrane and have no rigid cell wall outside it. A cell wall is found in plants, where it is made mainly of cellulose, in fungi, where it is made of chitin, and in bacteria, where it is made of peptidoglycan.
Read the full explanation →A student was doing an experiment on increasing the cell division among plants. She asked her supervisor to suggest the specific plant hormone for the same. Had you been her supervisor, which plant hormone would you suggest?
- A.Abscisic acid
- B.Gibberellins
- C.Cytokinin
- D.Auxin
Show answer
Cytokinins are the plant hormones whose main job is to promote cell division, or cytokinesis, which gives them their name.
Read the full explanation →The human eye has a point that lacks photoreceptor cells. This is identified as :
- A.Fovea
- B.Blind spot
- C.Dark spot
- D.Orbit
Show answer
The blind spot is the place where the optic nerve leaves the eye, and it has no rods or cones, so light falling there is not seen.
Read the full explanation →