The two elements that are frequently used for making transistors are--

(A) Boron and aluminium

(B) Silicon and germanium

(C) Iridium and tungsten

(D) Niobium and columbium

Which of the following gases is not known as a greenhouse gas?

(A) Carbon dioxide

(B) Methane

(C) Nitrous oxide

(D) Chlorofluorocarbons

Match the following.

Consider the following statements regarding graphite:
$1.$ It is an allotrope of carbon.
$2.$ It is a good conductor of heat and electricity.
$3.$ It can be artificially produced.

Select the correct statement from the following.

Chemical formula for water glass is--

(A) Na₂SiO₃

(B) Al₂O₃

(C) NaAlO₂

(D) CaSiO₃

The gases used in different types of welding would include-

(A) Oxygen and hydrogen

(B) Oxygen, acetylene, and argon

(C) Oxygen, acetylene

(D) Oxygen, hydrogen, acetylene and, nitrogen

Potassium nitrate is used in:

(A) Salt

(B) Glass

(C) Fertiliser

(D) Medicine

In which type of rocks are metals like gold and copper mostly found?

(A) Old igneous

(B) Old sedimentary

(C) Old metamorphic

(D) New metamorphic