Advertisements
Advertisements
प्रश्न
What name is given to those elements which are neither good conductors of electricity like copper nor insulators like sulphur ?
उत्तर
Elements that are neither good nor bad conductors of electricity, are called semi conductors.
APPEARS IN
संबंधित प्रश्न
The molecules can move freely anywhere in
Liquids have definite shape and definite volume.
The best evidence for the existence and movement of particles in liquids was provided by :
Name two solid, two liquid and two gaseous elements at the room temperature.
How would you confirm that a colourless liquid given to your is pure water ?
What are (i) metals (ii) non-metals, and (iii) metalloids ? Give two examples each of metals, non-metals and metalloids.
There are three substances X, Y and Z. The substance X does not have a fixed melting point or boiling point and it still shows the individual properties of its constituents. The substance Y is a pure substance which occurs in nature as such. The substance Y has a fixed melting point and boiling point but it cannot be broken down into simpler substances by any chemical means. The substance Z is also a pure substance whose properties are entirely different from those of its constituents. The substance Z can, however, be divided by electrolysis into two substances which belong to the same class of substances as Y.
- What type of substance could X be ? Name one substance like X.
- What type of substance could Y be ? Name one substance like Y.
- What type of substance could Z be ? Name one substance like Z.
- Which process involves absorption or release of an appreciable amount of energy : formation of substance X or formation of substance Z ?
- Name the three groups into which all the substances like Y are divided on the basis of their properties.
There is a large group of materials P which can be divided into three groups Q, R and S on the basis of their properties. The substances belonging to group Q can be solids, liquids or gases. The solids belonging to group Q are usually electrical insulators. Most of the substances of group R are solids which are good conductors of electricity. The substances belonging to group S are neither insulators like Q nor good conductors like R. The properties of S are intermediate between those of Q and R.
- What could the group of materials P be ?
- Name the substances Q. Give two examples of such substances.
- Name the substances R. Write two examples of such substances.
- Name the substances S. Give two examples of such substances.
- Out of Q, R and S, which substances are malleable and ductile ?
A, B and C are all liquids. Liquid A has a comparatively low boiling point. On heating, liquid A vaporises completely without leaving behind any residue. Liquid A is being used increasingly as a fuel in motor vehicles either alone or by mixing with petrol. Liquid B has a very high boiling point. It also vaporises completely on heating, without leaving any residue. Liquid B is a conductor of electricity and used in making thermometers. Liquid C has a moderate boiling point. On heating, liquid C vaporises leaving behind a white solid D which is used in cooking vegetables. The condensation of vapours from C give a liquid E which turns anhydrous CuSO4 to blue.
(a) Which liquid could be an element ? Name this element.
(b) Which liquid could be a mixture ? Name this mixture.
(c) Which liquid could be a compound ? Name this compound.
(d) What could the solid D be ?
(e) What do you think is liquid E ?
Define solubility of a substance. How does it vary with temperature ?
One of the following is a solid foam. This one is :
Which of the following represents the solubility of sugar in water at 20°C ?
One of the following liquids will leave behind a residue on heating. This one is :
Which of the following can be called a suspension ?
Name the process by which all the dye can be recovered from black ink.
Explain how, impure copper sulphate can be purified by crystallisation.
Asmita went to buy an earthen pot. There she saw many things kept for sale.
How did she identify what she needed?
Which among the following is not a matter?
You want to wear your favourite shirt to a party, but the problem is that it is still wet after a wash. What steps would you take to dry it faster?
Compressibility of solids: ______.