Test: JEE Main 35 Year PYQs- Modern Physics - JEE MCQ

Test: JEE Main 35 Year PYQs- Modern Physics - JEE MCQ

Test Description

30 Questions MCQ Test Chapter-wise Tests for JEE Main & Advanced - Test: JEE Main 35 Year PYQs- Modern Physics

Test: JEE Main 35 Year PYQs- Modern Physics for JEE 2024 is part of Chapter-wise Tests for JEE Main & Advanced preparation. The Test: JEE Main 35 Year PYQs- Modern Physics questions and answers have been prepared according to the JEE exam syllabus.The Test: JEE Main 35 Year PYQs- Modern Physics MCQs are made for JEE 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Test: JEE Main 35 Year PYQs- Modern Physics below.
Solutions of Test: JEE Main 35 Year PYQs- Modern Physics questions in English are available as part of our Chapter-wise Tests for JEE Main & Advanced for JEE & Test: JEE Main 35 Year PYQs- Modern Physics solutions in Hindi for Chapter-wise Tests for JEE Main & Advanced course. Download more important topics, notes, lectures and mock test series for JEE Exam by signing up for free. Attempt Test: JEE Main 35 Year PYQs- Modern Physics | 113 questions in 220 minutes | Mock test for JEE preparation | Free important questions MCQ to study Chapter-wise Tests for JEE Main & Advanced for JEE Exam | Download free PDF with solutions
Test: JEE Main 35 Year PYQs- Modern Physics - Question 1

If 13.6 eV energy is required to ionize the hydrogen atom, then the energy required to remove an electron from n = 2 is

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 1

KEY CONCEPT : The energy of  nth orbit of hydrogen is given by

Therefore the energy required to remove electron from n = 2 is + 3.4 eV.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 2

At absolute zero, Si acts as

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 2

Pure silicon, at absolute zer o, will contain al l the electrons in bounded state. The conduction band will be empty. So there will be no free electrons (in conduction band) and holes (in valence band) due to thermal agitation. Pure silicon will act as insulator.

 1 Crore+ students have signed up on EduRev. Have you?
Test: JEE Main 35 Year PYQs- Modern Physics - Question 3

At a specific instant emission of radioactive compound is deflected in a magnetic field. The compound can emit (i) electrons (ii) protons (iii) He2+ (iv) neutrons The emission at instant can be

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 3

Charged particles are deflected in magnetic field.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 4

Sodium and copper have work functions 2.3 eV and 4.5 eV respectively. Then the ratio of the wavelengths is nearest to

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 4

We know that work function is the energy required and energy E = hu

Test: JEE Main 35 Year PYQs- Modern Physics - Question 5

Formation of covalent bonds in compounds exhibits

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 5

For mation of covalent bond is best explain ed by molecular orbital theory.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 6

If N0 is the original mass of the substance of half-life period t1/2 = 5 years, then the amount of substance left after 15 years is

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 6

After every half-life, the mass of the substance reduces to half its initial value.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 7

By increasing the temperature, the specific resistance of a conductor and a semiconductor

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 7

Specific resistance is resistivity which is given by

where n  = no. of free electrons per unit volume and τ  = average relaxation time For a conductor with  rise in temperature n increases and τ decreases. But decrease in t is more dominant than increase in n resulting an increase in the value of ρ.
For a semiconductor with rise in temperature, n increases and τ decreases. But the increase in n is more dominant than decrease in τ resulting in a decrease in the value of ρ.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 8

The energy band gap is maximum in

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 8

The energy band gap is maximum in insulators.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 9

The part of a transistor which is most heavily doped to produce large number of majority carriers is

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 9

Emitter sends the majority charge carrriers towards the collector. Therefore emitter is most heavily doped.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 10

Which of the following are not electromagnetic waves?

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 10

β -rays are fast moving beam of electrons.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 11

A strip of copper and another of germanium are cooled from room temperature to 80K. The resistance of

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 11

The resist ance of metal (like Cu) decr eases with decrease in temperature whereas the resistance of a semi-conductor (like Ge) increases with decrease in temperature.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 12

Which of the following radiations has the least wavelength ?

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 12

The electromagnetic spectrum is as follows

∴ γ-rays has least wavelength

Test: JEE Main 35 Year PYQs- Modern Physics - Question 13

When a U238 nucleus originally at rest, decays by emitting an alpha particle having a speed ‘u’, the recoil speed of the residual nucleus is

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 13

(c) : Linear momentum is conserved

Test: JEE Main 35 Year PYQs- Modern Physics - Question 14

The difference in the variation of resistance with temeperature in a metal and a semiconductor arises essentially due to the difference in the

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 14

When the temperature increases, certain boun ded electrons become free which tend to promote conductivity. Simultaneously  number of collisions between electrons and positive kernels increases

Test: JEE Main 35 Year PYQs- Modern Physics - Question 15

A radioactive sample at any instant has its disintegration rate 5000 disintegrations per minute. After 5 minutes, the rate is 1250 disintegrations per minute. Then, the decay constant (per minute) is

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 15

Test: JEE Main 35 Year PYQs- Modern Physics - Question 16

A nucleus with Z = 92 emits the following in a sequence:

Then Z of the resulting nucleus is

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 16

The number of  α - particles released = 8 Therefore the atomic number should decrease by 16
The number of β- -particles released = 4
Therefore the atomic number should increase by 4.
Also the number of β+ particles released is 2, which should decrease the atomic number by 2.
Therefore the final atomic number is
92 –16 + 4 – 2 = 78

Test: JEE Main 35 Year PYQs- Modern Physics - Question 17

Two identical photocathodes receive light of frequencies f1 and f2. If the velocites of the photo electrons (of mass m) coming out are respectively v1 and v2, then

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 17

For one photocathode

For another photo cathode

Subtracting (ii) from (i) we get

Test: JEE Main 35 Year PYQs- Modern Physics - Question 18

Which of the following cannot be emitted by radioactive substances during their decay ?

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 18

The radioactive substances emit α -particles (Helium nucleus), β – particles (electrons) and neutrinoes.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 19

In the nuclear fusion reaction

given that the repulsive potential energy between the two nuclei is ~ 7.7 × 10 -14 J , the temperature at which the gases must be heated to initiate the reaction is nearly [Boltzmann’s Constant k = 1.38 × 10 -23 J/K]

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 19

The average kinetic energy per molecule

This kinetic energy should be able to provide the repulsive potential energy

Test: JEE Main 35 Year PYQs- Modern Physics - Question 20

Which of the following atoms has the lowest ionization potential ?

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 20

The ionisation potential increases from left to right in a period and decreases from top to bottom in a group.
Therefore ceasium will have the lowest ionisation potential.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 21

The wavelengths involved in the spectrum of deuterium  are slightly different from that of  hydrogen spectrum, because

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 21

The wavelength of spectrum is given by

where m = mass of electron
M = mass of nucleus.
For different M, R is different and therefore λ is different

Test: JEE Main 35 Year PYQs- Modern Physics - Question 22

In the middle of the depletion layer of a reverse- biased p-n junction, the

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 22

As in reverse bias, the current through the 0000 is zero through the electric field is also zero.

Test: JEE Main 35 Year PYQs- Modern Physics - Question 23

If the binding energy of  the electron in a hydrogen atom is 13.6eV,  the energy required to remove the electron from the first excited state of Li ++ is

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 23

For lithium ion  Z = 3  ; n = 2  (for first excited state)

Test: JEE Main 35 Year PYQs- Modern Physics - Question 24

A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 24

Momentum of photon = E/c

Change in momentum = 2E/c

= momentum transferred to the surface(the photon will reflect with same magnitude of momentum in opposite direction)

Test: JEE Main 35 Year PYQs- Modern Physics - Question 25

According to Einstein’s photoelectric equation, the plot of the kinetic energy of the emitted photo electrons from a metal Vs the frequency, of the incident radiation gives as straight the whose slope

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 25

From E quation K .E = hv-φ
slope of graph of  K.E  & v is h (Plank's constant) which is same for all metals

Test: JEE Main 35 Year PYQs- Modern Physics - Question 26

The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately.

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 26

For the longest wavelength to emit photo electron

Test: JEE Main 35 Year PYQs- Modern Physics - Question 27

A nucleus disintegrated into two nuclear parts which have their velocities in the ratio of 2 : 1. The ratio of their nuclear sizes will be

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 27

From conservation of momentum m1v1 = m2v2

Test: JEE Main 35 Year PYQs- Modern Physics - Question 28

The binding energy per nucleon of deuteron  and helium nucleus  is 1.1 MeV and 7 MeV respectively.. If two deuteron nuclei react to form a single helium nucleus, then the energy released is

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 28

The nuclear reaction of  process is  He Energy released  = 4 × (7) – 4(1.1) = 23.6 MeV

Test: JEE Main 35 Year PYQs- Modern Physics - Question 29

An α-particle of energy 5 MeV is scattered through 180º by a fixed uranium nucleus. The distance of closest approach is of the order of

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 29

KEY CONCEPT :

Distance of closest approach

Test: JEE Main 35 Year PYQs- Modern Physics - Question 30

When npn transistor is used as an amplifier

Detailed Solution for Test: JEE Main 35 Year PYQs- Modern Physics - Question 30

Electrons move from base to emmitter.

Chapter-wise Tests for JEE Main & Advanced

447 docs|930 tests
Information about Test: JEE Main 35 Year PYQs- Modern Physics Page
In this test you can find the Exam questions for Test: JEE Main 35 Year PYQs- Modern Physics solved & explained in the simplest way possible. Besides giving Questions and answers for Test: JEE Main 35 Year PYQs- Modern Physics, EduRev gives you an ample number of Online tests for practice

Chapter-wise Tests for JEE Main & Advanced

447 docs|930 tests