In p-type semiconductors, the conductivity is due to:

The reagent involved in Lucas test is

An element ' \(Y\) ' has a body centred cubic (bec) structure with a cell edge of 144 pm . The density of the element is \(3.6 g / cm ^3\). How many atoms are present in 720 g of the element?

Arrange the following transition elements of the first series in increasing order of their densities
(A) Sc
(B) V
(C) Zn
(D) Cu
Choose the correct answer from the options given below :

Question based on the following passage :
P-Block elements are placed in group 13 to 18 in the periodic table. Group 15 is nitrogen family.
Nitrogen can react with hydrogen, oxygen, halogens etc. It shows multiple oxidation states in its various oxides i.e. \(N_2O, N_2O_3, N_2O_5\) etc. Important allotropic forms of phosphorus are white, red and black phosporus. Various compounds of phosphorus are phosphine, \(PCl_3, PCl_5\) and oxoacids of phosphorus. Oxidation states \(+1\) to \(+5\) are seen in various oxoacids of phosphorus. Group 17 elements are collectively known as halogens. Bond dissociation enthalpy of \(F_2\) is smaller than \(Cl_2\).
The gases present in group 18 are chemically unreactive, they form only few compounds. Neil Bartlett (in 1962) observed the reaction of a noble gas. Since then, many noble gas compounds have been synthesised.
The process used for the preparation of Oleum is :

Identify the incorrect statement
A. Bakelite and urea-formaldehyde resins are elastomers
B. Polyamides like nylon 6, nylon 6, 6 are the examples of fibers.
C. Polystyrene, polyvinylchloride and polythene are thermoplastic polymers.
D. Thermoplastic polymers have intermolecular force between elastomers and fibers.
Choose the most appropriate answer from the options given below:

Allyl chloride on dehydrochlorination gives:

Which of the following equations represents the Ampere-Maxwell law?

The reaction occurring at the cathode during discharging of a lead-storage battery is:

Match List-l with List-II

List-I (Terms)	List-II (Examples)
(A) Divergent evolution	(I) Eye of the octopus and mammals
(B) Convergent evolution	(II) Forelimbs in vertebrate animals
(C) Evolution by anthropogenic action	(III) Australian marsupials
(D) Adaptive radiation	(IV) Industrial melanization in moth

Choose the correct answer from the options given below:

Plants can capture only 2-10% of the PAR and this small amount of energy sustains the entire world. Here PAR stands for:

Answer the question on basis of passage given below :
Molecular nitrogen is very little reactive chemically. During lightning discharge, atmospheric nitrogen and oxygen combines to form nitric oxide which also combines with oxygen to form nitrogen dioxide. Both NO and \(NO _2\) constitute smog which is very poisonous. It can cause burning sensasion in the eyes and adversely affect respiratory system.
What is the colour of nitrogen dioxide.

Two point charges of \( 1 \times 10^{-6} \, C \) and \( 4 \times 10^{-6} \, C \) are placed at a certain distance away from each other. The resultant electric field intensity is zero at a distance of 15 cm from the charge \( 1 \times 10^{-6} \, C \). The distance between the two point charges will be :