Consider the following statements : 1. Particles of matter intermix on their own. 2. Particles of matter have force acting between them. Which of the statements given above is/are correct?
- A.1 only
- B.2 only
- C.Both 1 and 2
- D.Neither 1 nor 2
Correct answer
Explanation
The correct answer is C, both 1 and 2. Particles of matter mix with one another on their own, and there are forces of attraction between them; both are basic properties taught in Class 9 science. The first is shown by diffusion. The smell of incense spreads through a room, and a crystal of potassium permanganate slowly colours a whole beaker of water, because the particles are always moving and slip into the spaces between other particles. Diffusion is fastest in gases, slower in liquids and slowest in solids, and it speeds up with heat. The second is shown by how hard it is to break an iron nail compared with a piece of chalk, or a rubber band compared with a stream of water: particles are held together by attraction, strongest in solids and weakest in gases. Option A is wrong because statement 2 is also true. Option B is wrong because statement 1 is also true. Option D is wrong because both statements are true. Exam tip: particles of matter have spaces between them, are always moving and attract one another.
Practice Questions
View allWhich one of the following is monatomic?
- A.Hydrogen
- B.Sulphur
- C.Phosphorus
- D.Helium
Show answer
A monatomic element exists as single, separate atoms. Helium is a noble gas of group 18: its only shell, the first, is full with two electrons, so a helium atom has no tendency to share or transfer electrons and does not bond even with another helium atom.
Read the full explanation →The normal systolic pressure in human beings is :
- A.80 mm of Hg
- B.100 mm of Hg
- C.120 mm of Hg
- D.140 mm of Hg
Show answer
Blood pressure is written as two numbers, and normal adult blood pressure is about 120/80 mm of mercury.
Read the full explanation →'Study of human societies and cultures from the oldest times to the present' is the work of
- A.Archaeologists
- B.Anthropologists
- C.Palaeontologists
- D.Geologists
Show answer
Anthropology, from the Greek 'anthropos' (human) and 'logos' (study), is the science of human beings: how societies and cultures began, how they changed and how people live today.
Read the full explanation →Which of the following catalytic systems is used for the reduction of unsaturated hydrocarbon to saturated hydrocarbon?
- A.Copper and H2
- B.Iron and H2
- C.Zinc and H2
- D.Nickel and H2
Show answer
Adding hydrogen across the double or triple bond of an alkene or alkyne turns it into a saturated alkane; this reaction is called hydrogenation and it needs a catalyst.
Read the full explanation →Which one among the following is not a plant hormone ?
- A.Gibberellins
- B.Abscisic acid
- C.Auxins
- D.Thyroxine
Show answer
Thyroxine is an animal hormone, made by the thyroid gland in the neck, and it controls the rate of metabolism in the human body.
Read the full explanation →