Which one of the following is not a semiconductor?
Which one of the following is a physical change?
Answer – C
- Heating of platinum crucible is a physical change as in this process formation of new substance do not take place and the change is reversible. Physical change is the change from one phase of matter (solid, liquid, or gas) to another and the substance is not altered
The pH value of a sample of multiple-distilled water is -
Which one of the following is the most characteristic property of an element ?
There are two elements--calcium (atomic number 20) and argon (atomic number 18). The mass number of both the elements is 40. They are therefore known as :
Plum Pudding Model - for an atom was proposed by :
The chemical properties of an element depend upon :
The paste of a white material in water is used to maintain a fractured bone fixed in place. The white material used is called :
Which one of the following types of glasses is used for making optical instruments?
What are the main constituents of biogas ?