All Courses
Get the App Signup / Login
Sign in Open App
JEE Exam  >  JEE Tests  >  COMEDK Mock Test - 9 - JEE MCQ

COMEDK Mock Test - 9 - JEE MCQ


Test Description

30 Questions MCQ Test - COMEDK Mock Test - 9

COMEDK Mock Test - 9 for JEE 2024 is part of JEE preparation. The COMEDK Mock Test - 9 questions and answers have been prepared according to the JEE exam syllabus.The COMEDK Mock Test - 9 MCQs are made for JEE 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for COMEDK Mock Test - 9 below.
Solutions of COMEDK Mock Test - 9 questions in English are available as part of our course for JEE & COMEDK Mock Test - 9 solutions in Hindi for JEE course. Download more important topics, notes, lectures and mock test series for JEE Exam by signing up for free. Attempt COMEDK Mock Test - 9 | 180 questions in 180 minutes | Mock test for JEE preparation | Free important questions MCQ to study for JEE Exam | Download free PDF with solutions
COMEDK Mock Test - 9 - Question 1
Save

A body at rest is moved along a horizontal straight line by a machine delivering a constant power. The distance moved by the body in time 't' is proportional to

Detailed Solution for COMEDK Mock Test - 9 - Question 1

P = constant

By integration,

COMEDK Mock Test - 9 - Question 2
Save

A cylindrical tank has a hole of diameter 2r in its bottom. The hole is covered wooden cylindrical block of diameter 4r, height h and density ρ/3.

Situation I : Initially, the tank is filled with water of density ρ to a height such that the height of water above the top of the block is h1 (measured from the top of the block).

Situation II : The water is removed from the tank to a height h2 (measured from the bottom of the block), as shown in the figure.
The height h2 is smaller than h (height of the block) and thus the block is exposed to the atmosphere.

Q. Find the minimum value of height h1 (in situation 1), for which the block just starts to move up?    

Detailed Solution for COMEDK Mock Test - 9 - Question 2

Consider the equilibrium of wooden block.
Forces acting in the downward direction are

(a) Weight of wooden cylinder

(b) Force due to pressure (P1) created by liquid of height h1 above the wooden block is
= P1 × π (2r)2 = [P0 + h1rg] × π (2r)2
Force acting on the upward direction due to pressure P2 exerted from below the wooden block and atmospheric pressure is

At the verge of rising

1 Crore+ students have signed up on EduRev. Have you? Download the App
COMEDK Mock Test - 9 - Question 3
Save

A point source of heat of power P is placed at the centre of a spherical shell of mean radius R. The material of the shell has thermal conductivity K. Calculate the thickness of the shell if the temperature difference between the outer and inner surfaces of the shell in steady-state is T.

Detailed Solution for COMEDK Mock Test - 9 - Question 3
Consider a concentric spherical shell of radius r and thickness dr as shown in diagram. The radial rate of flow of heat through this shell in steady state will be,

[Negative sign is used as with increase in r, θ decreases.]

Now as for spherical shell A = 4πr2

which on integration and simplification gives

Now in steady state as no heat is absorbed, rate of loss of heat by conduction is equal to that of supply, i.e., H = P, and here

θ1 - ​θ2 = T and a ≃ b = Ra ≃ b = R

So Equation (i) becomes,

i.e., thickness of shell

COMEDK Mock Test - 9 - Question 4
Save

A particle of mass m and charge q has an initial velocity . If an electric field  and magnetic field  act on the particle, its speed will be doubled after a time:
Detailed Solution for COMEDK Mock Test - 9 - Question 4

Given,

Now we see that the velocity is perpendicular to the magnetic field so the magnitude of velocity will not change due to magnetic field.
The magnitude of velocity will change in 'i' direction due to  only

Let us say that the speed of particle doubles after time 't'. in y direction the speed will be V0 only in y - z plane always perpendicular to x-direction so net speed at time 't'.

Also by given condition Vnet = 2V0

COMEDK Mock Test - 9 - Question 5
Save

A 25 m long antenna is mounted on an antenna tower. The height of the antenna tower is 75 m. The wavelength (in metres) of the signal transmitted by this antenna would be:
Detailed Solution for COMEDK Mock Test - 9 - Question 5

Length of the antenna = 25 m
 = λ / 4
⇒ λ = 100m

COMEDK Mock Test - 9 - Question 6
Save

A sphere of mass m and diameter D is Heated by temperature ΔT , if Coefficient of linear expansion is α what will be the change in the Surface Area
Detailed Solution for COMEDK Mock Test - 9 - Question 6

Initial Surface Area = 4πR2
= 4 π (D/2)2
= 4 π D2 / 4 = π D2
Surface Area at ΔT
= 4π(D'/2)2
Now
D'=D(1+α ΔT)
So Surface Area at ΔT
= 4π(D2/4 )(1+α ΔT)2
= π D2 (1+ α2ΔT2 + 2α ΔT)
Change in surface Area
= π D2 (α2ΔT2 + 2α ΔT)
= π D2α ΔT (α ΔT+ 2)

COMEDK Mock Test - 9 - Question 7
Save

What is the rest mass energy of an electron?
Detailed Solution for COMEDK Mock Test - 9 - Question 7

COMEDK Mock Test - 9 - Question 8
Save

When a system is taken from state i to state f along the path iaf, it is found that Q = 50 cal and W = 20 cal. Along the path ibf, Q = 36 cal. W along the path ibf is
Detailed Solution for COMEDK Mock Test - 9 - Question 8

According to first law of thermodynamics, for the path iaf,

Qiaf = ΔUiaf + Wiaf

or, ΔUiaf = Qiaf - Wiaf

= 50 - 20 = 30 cal

For the path ibf,

Qibf = ΔUiaf + Wibf

Since ΔUiaf = ΔUibf, change in internal energy is path independent.

Qibf = ΔUiaf + Wiaf

∴ Wibf = Qibf - ΔUiaf = 36 - 30 = 6 cal

COMEDK Mock Test - 9 - Question 9
Save

Spherical wavefronts shown in figure, strike a plane mirror. Reflected wavefronts will be as shown in
Detailed Solution for COMEDK Mock Test - 9 - Question 9
According to Huygens principle, ray of light will be normal to the wavefront.

COMEDK Mock Test - 9 - Question 10
Save

Chemical 'A' is used to the remove temporary hardness of water. 'A' reacts with sodium carbonate to give caustic soda. On bubbling CO2 through the solution of A, a milkiness is observed. The chemical formula of A is:
Detailed Solution for COMEDK Mock Test - 9 - Question 10

The reaction of sodium carbonate with slaked lime to produce caustic soda is as follows:

Also, Ca(OH)2 when bubbled with CO2 gives milkiness due to the formation of calcium carbonate.

Bicarbonates of Ca and Mg present in the water result in temporary hardness. These bicarbonates react with slaked lime to form insoluble calcium and magnesium carbonates, which can be easily filtered off.

This is known as Clark's method to remove temporary hardness.

COMEDK Mock Test - 9 - Question 11
Save

One atom of an element y weights 6.64 x 10-23 g. Then, find the numbers of moles of atom in 20 kg
Detailed Solution for COMEDK Mock Test - 9 - Question 11

COMEDK Mock Test - 9 - Question 12
Save

In the reaction, 2N2O5(g) → 4NO2(g) + O2(g)  if the concentration of NO2 increase by 5.2 x 10−3 M in 100 seconds then what will be the rate of the reactions?
Detailed Solution for COMEDK Mock Test - 9 - Question 12

From balanced chemical reaction

COMEDK Mock Test - 9 - Question 13
Save

Which of the following molecule is expected to rotate the plane of polarised light?
Detailed Solution for COMEDK Mock Test - 9 - Question 13

Optically active compounds rotate the plane of polarised light either towards the right or left side. And the compound which has at least one chiral centre will be optically active.

Since only the given compound contains a chiral carbon, it will rotate the plane of polarised light.

Option D also has chiral carbons but it also contain plane of symmetry. So, it will be meso compound.

COMEDK Mock Test - 9 - Question 14
Save

A solid AB has a NaCl structure. If the radius of cation A+ is 120 pm, then the maximum possible value of the radius of the anion B- will be
Detailed Solution for COMEDK Mock Test - 9 - Question 14

For a NaCl crystal, Cl- ions form the FCC lattice and Na+ ions lie in the octahedral voids.
The minimum value of radius ratio (radius of cation/radius of anion) in an octahedral void is 0.414.

COMEDK Mock Test - 9 - Question 15
Save

At 25°C, the dissociation constant of a base, BOH, is 1.0 x 10-12. The concentration of hydroxyl ions in 0.01 M aqueous solution of the base would be
Detailed Solution for COMEDK Mock Test - 9 - Question 15

Base BOH is dissociated as follows.

So, dissociation constant of BOH base,

At equilibrium, [B+] = [OH]-

COMEDK Mock Test - 9 - Question 16
Save

Which of the following is the true covalent oxide of iodine?
Detailed Solution for COMEDK Mock Test - 9 - Question 16

In general, higher the oxidation state, more is the covalent character of the oxide. Therefore, the only covalent oxide of iodine is I2O5, whereas I2O7 and I2O9 do not exist and I2O4 is iodyl iodate, i.e. [IO]+[IO3]-, which is ionic in nature.

COMEDK Mock Test - 9 - Question 17
Save

What is the time (in sec) required for depositing all the silver present in 125 mL of 1 M AgNO3 solution by passing a current of 241.25 A?
(1F = 96500 coulombs)
Detailed Solution for COMEDK Mock Test - 9 - Question 17

Given 125 mL of 1 M AgNO3 solution.

1000 mL of AgNO3 solution contains 108 g Ag.

 125 mL of AgNO3 solution contains

COMEDK Mock Test - 9 - Question 18
Save

Here, Z is
COMEDK Mock Test - 9 - Question 19
Save

In a certain operation, 358 g of TiCl4 reacts with 96 g of Mg. Calculate the yield of Ti. if 32 g is actually obtained [atomic weight of Ti =48, atomic weight of Mg=24]
Detailed Solution for COMEDK Mock Test - 9 - Question 19

Balanced equation :

For finding limiting reagent, moles of both the reactants are divided by their coefficients and the least value gives L.R.

∴ TiCl4 is the limiting reagent So, on the basis of L.R., product amount will be calculated.

∵ One mole of TiCl4 produces one mole of Ti.

 Number of moles of Ti produced by 1.88 moles of 

TiCl4 = 1.88 moles.

Mass of Ti= moles of Ti x molar mass of Ti

COMEDK Mock Test - 9 - Question 20
Save

The stability of lyophilic colloids is due to which of the following?
Detailed Solution for COMEDK Mock Test - 9 - Question 20

Lyophilic colloids have very less or no charge and their particle size is within colloidal range.

So, charge and size do not show any effect on stability.

But they are highly solvated in the dispersion medium, they exist and remain stable. So, dispersion medium is the reason behind the existence of lyophilic colloids in stable form.

COMEDK Mock Test - 9 - Question 21
Save

A mixture of N2 and Ar gases in a cylinder contains 7 g of N2 and 8 g of Ar. If the total pressure of the mixture of the gases in the cylinder is 27 bar, the partial pressure of N2 is:
[Use atomic masses (in g mol–1): N=14,Ar=40]
Detailed Solution for COMEDK Mock Test - 9 - Question 21

COMEDK Mock Test - 9 - Question 22
Save

The standard Gibbs free energy change and enthalpy change at 25oC for the liquid phase reaction 

are given as ΔG0298 = -4650 J/mol and ΔH0298 = -3640 J/mol. If the solution is ideal and enthalpy change is assumed to be constant, then the equilibrium constant at 95oC is
Detailed Solution for COMEDK Mock Test - 9 - Question 22

COMEDK Mock Test - 9 - Question 23
Save

The difference between heat of reaction at constant pressure and constant volume for the reaction 2C6H6 (l) + 15SO2 (g) 12 CO2 (g) + 6H2O (l) + 15S (s) at 25oC in kJ mol-1 is
Detailed Solution for COMEDK Mock Test - 9 - Question 23

COMEDK Mock Test - 9 - Question 24
Save

If the aqueous solutions of the following salts are electrolysed for 1 h with 10 A current, then which of the following solutions will deposit the maximum mass of the metal at the cathode?
(The atomic weights are Fe = 56 u, Zn = 65 u, Ag = 108 u, Hf = 178 u and W = 184 u)
Detailed Solution for COMEDK Mock Test - 9 - Question 24

According to Faraday' first law of electrolysis:

The euivalent weight of Ag is maximum among these hence, AgNO3 solution will deposit the maximum mass of the metal at the cathode on electrolysis.

COMEDK Mock Test - 9 - Question 25
Save

COMEDK Mock Test - 9 - Question 26
Save

   is continuous at x = 0, then k =
COMEDK Mock Test - 9 - Question 27
Save

The differential equation which represents the family of plane curves y=exp. (cx) is
Detailed Solution for COMEDK Mock Test - 9 - Question 27

y = ecx
dy/dx = c. ecx
y' = cy

COMEDK Mock Test - 9 - Question 28
Save

Integrating factor of  

COMEDK Mock Test - 9 - Question 29
Save

∫[(sec2x)/(1+tanx)] dx =
COMEDK Mock Test - 9 - Question 30
Save

The area bounded by the parabola x = 4 − y2 and the y-axis, in square units is
View more questions
Information about COMEDK Mock Test - 9 Page
In this test you can find the Exam questions for COMEDK Mock Test - 9 solved & explained in the simplest way possible. Besides giving Questions and answers for COMEDK Mock Test - 9, EduRev gives you an ample number of Online tests for practice

Top Courses for JEE

Download as PDF

Top Courses for JEE

Important Questions for COMEDK Mock Test - 9

Find all the important questions for COMEDK Mock Test - 9 at EduRev.Get fully prepared for COMEDK Mock Test - 9 with EduRev's comprehensive question bank and test resources. Our platform offers a diverse range of question papers covering various topics within the COMEDK Mock Test - 9 syllabus. Whether you need to review specific subjects or assess your overall readiness, EduRev has you covered. The questions are designed to challenge you and help you gain confidence in tackling the actual exam. Maximize your chances of success by utilizing EduRev's extensive collection of COMEDK Mock Test - 9 resources.

COMEDK Mock Test - 9 MCQs with Answers

Prepare for the COMEDK Mock Test - 9 within the JEE exam with comprehensive MCQs and answers at EduRev. Our platform offers a wide range of practice papers, question papers, and mock tests to familiarize you with the exam pattern and syllabus. Access the best books, study materials, and notes curated by toppers to enhance your preparation. Stay updated with the exam date and receive expert preparation tips and paper analysis. Visit EduRev's official website today and access a wealth of videos and coaching resources to excel in your exam.

Online Tests for COMEDK Mock Test - 9

Practice with a wide array of question papers that follow the exam pattern and syllabus. Our platform offers a user-friendly interface, allowing you to track your progress and identify areas for improvement. Access detailed solutions and explanations for each test to enhance your understanding of concepts. With EduRev's Online Tests, you can build confidence, boost your performance, and ace COMEDK Mock Test - 9 with ease. Join thousands of successful students who have benefited from our trusted online resources.
© EduRev
Education Revolution
Signup to see your scores go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup