1

IIT-JEE 2011 Paper 1 Offline

MCQ (Single Correct Answer)

+3

-0.75

A dense collection of equal number of electrons and positive ions is called neutral plasma. Certain solids containing
fixed positive ions surrounded by free electrons can be treated as neutral plasma. Let 'N' be the number density of
free electrons, each of mass 'm'. When the electrons are subjected to an electric field, they are displaced relatively
away from the heavy positive ions. If the electric field becomes zero, the electrons begin to oscillate about the
positive ions with a natural angular frequency '$${\omega _p}$$' which is called the plasma frequency. To sustain the oscillations,
a time varying electric field needs to be applied that has an angular frequency $$\omega $$, where a part of the energy is
absorbed and a part of it is reflected. As $$\omega $$ approaches $${\omega _p}$$ all the free electrons are set to resonance together and all
the energy is reflected. This is the explanation of high reflectivity of metals.

Taking the electronic charge as 'e' and the permittivity as $$'{\varepsilon _0}'$$. Use dimensional analysis to determine the correct expression for $${\omega _p}$$.

2

IIT-JEE 2011 Paper 1 Offline

MCQ (Single Correct Answer)

+3

-0.75

A dense collection of equal number of electrons and positive ions is called neutral plasma. Certain solids containing
fixed positive ions surrounded by free electrons can be treated as neutral plasma. Let 'N' be the number density of
free electrons, each of mass 'm'. When the electrons are subjected to an electric field, they are displaced relatively
away from the heavy positive ions. If the electric field becomes zero, the electrons begin to oscillate about the
positive ions with a natural angular frequency '$${\omega _p}$$' which is called the plasma frequency. To sustain the oscillations,
a time varying electric field needs to be applied that has an angular frequency $$\omega $$, where a part of the energy is
absorbed and a part of it is reflected. As $$\omega $$ approaches $${\omega _p}$$ all the free electrons are set to resonance together and all
the energy is reflected. This is the explanation of high reflectivity of metals.

Estimate the wavelength at which plasma reflection will occur for a metal having the density of electrons
N $$ \approx $$ 4 $$ \times $$ 10^{27} m^{-3}. Taking $${{\varepsilon _0}}$$ = 10^{- 11} and m $$ \approx $$ 10^{- 30}, where these quantities are in proper SI units.

3

IIT-JEE 2011 Paper 2 Offline

MCQ (Single Correct Answer)

+3

-0.75

The density of a solid ball is to be determined in an experiment. The diameter of the ball is measured with
a screw gauge, whose pitch is 0.5 mm and there are 50 divisions on the circular scale. The reading on the
main scale is 2.5 mm and that on the circular scale is 20 divisions. If the measured mass of the ball has a
relative error of 2 %, the relative percentage error in the density is

4

IIT-JEE 2010 Paper 2 Offline

MCQ (Single Correct Answer)

+4

-1

A vernier calipers has 1 mm marks on the main scale. It has 20 equal divisions on the Vernier scale which match with 16 main scale divisions. For this Vernier calipers, the least count is

Questions Asked from Units & Measurements (MCQ (Single Correct Answer))

Number in Brackets after Paper Indicates No. of Questions

JEE Advanced 2022 Paper 2 Online (1)
JEE Advanced 2021 Paper 1 Online (1)
JEE Advanced 2018 Paper 1 Offline (4)
JEE Advanced 2017 Paper 2 Offline (1)
JEE Advanced 2016 Paper 2 Offline (1)
JEE Advanced 2013 Paper 2 Offline (1)
JEE Advanced 2013 Paper 1 Offline (1)
IIT-JEE 2012 Paper 1 Offline (1)
IIT-JEE 2011 Paper 1 Offline (2)
IIT-JEE 2011 Paper 2 Offline (1)
IIT-JEE 2010 Paper 2 Offline (1)
IIT-JEE 2008 Paper 1 Offline (1)
IIT-JEE 2007 (1)
IIT-JEE 2007 Paper 2 Offline (1)
IIT-JEE 2006 (2)
IIT-JEE 2005 Screening (1)
IIT-JEE 2004 Screening (2)
IIT-JEE 2003 Screening (1)
IIT-JEE 2001 Screening (1)
IIT-JEE 2000 Screening (1)

JEE Advanced Subjects

Physics

Mechanics

Units & Measurements
Motion
Laws of Motion
Work Power & Energy
Impulse & Momentum
Rotational Motion
Properties of Matter
Heat and Thermodynamics
Simple Harmonic Motion
Waves
Gravitation

Electricity

Optics

Modern Physics

Chemistry

Physical Chemistry

Some Basic Concepts of Chemistry
Structure of Atom
Redox Reactions
Gaseous State
Equilibrium
Solutions
States of Matter
Thermodynamics
Chemical Kinetics and Nuclear Chemistry
Electrochemistry
Solid State & Surface Chemistry

Inorganic Chemistry

Periodic Table & Periodicity
Chemical Bonding & Molecular Structure
Isolation of Elements
Hydrogen
s-Block Elements
p-Block Elements
d and f Block Elements
Coordination Compounds
Salt Analysis

Organic Chemistry

Mathematics

Algebra

Quadratic Equation and Inequalities
Sequences and Series
Mathematical Induction and Binomial Theorem
Matrices and Determinants
Permutations and Combinations
Probability
Vector Algebra and 3D Geometry
Complex Numbers

Trigonometry

Coordinate Geometry

Calculus