KEAM Paper 1 Mock Test - 7 - JEE MCQ

# KEAM Paper 1 Mock Test - 7 - JEE MCQ

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## 120 Questions MCQ Test KEAM Mock Test Series 2024 - KEAM Paper 1 Mock Test - 7

KEAM Paper 1 Mock Test - 7 for JEE 2024 is part of KEAM Mock Test Series 2024 preparation. The KEAM Paper 1 Mock Test - 7 questions and answers have been prepared according to the JEE exam syllabus.The KEAM Paper 1 Mock Test - 7 MCQs are made for JEE 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for KEAM Paper 1 Mock Test - 7 below.
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KEAM Paper 1 Mock Test - 7 - Question 1

### A gamma ray photon creates an electron-positron pair. If the rest mass energy of an electron is 0.5 MeV and the total K.E of the electron-positron pair is 0.78 MeV, then the energy of the gamma ray photon must be

KEAM Paper 1 Mock Test - 7 - Question 2

### Which of the following spectral series in hydrogen atom give spectral line of 4860 Å

KEAM Paper 1 Mock Test - 7 - Question 3

### A 220 V, 1000 W bulb is connected across a 110 V mains supply. The power consumed will be

KEAM Paper 1 Mock Test - 7 - Question 4

We have a galvanometer of resistance 25 Ω. It is shunted by a 2.5 Ω wire. The part of total current that flows through the galvanometer is given as

KEAM Paper 1 Mock Test - 7 - Question 5

Cathode rays are produced when the pressure is of the order of

KEAM Paper 1 Mock Test - 7 - Question 6

Light appears to travel in a straight line because

KEAM Paper 1 Mock Test - 7 - Question 7

Which of the following rays has minimum frequency?

KEAM Paper 1 Mock Test - 7 - Question 8

Three point charges 1C, 2C, − 2C are placed at the vertices of an equilateral triangle of side one metre. The work done by an external force to increase the separation of the charges to 2 metres in joules is( ∈ 0 is permittivity of air.

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 8

Initially and finally the net force is zero.
i.e. work done by the external force is zero

KEAM Paper 1 Mock Test - 7 - Question 9

Capacitance of a capacitor becomes 7/6 times its original value if a dielectric slab of thickness, t = 2/3 d is introduced in between the plates. 'd' is the separation between the plates. The dielectric constant of the dielectric slab is

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 9

KEAM Paper 1 Mock Test - 7 - Question 10

A space ship is launched into a circular orbit of radius R close to surface of earth. The additional velocity to be imparted to the space ship in the orbit to overcome the earth's gravitational pull is [g - acceleration due to gravity]

KEAM Paper 1 Mock Test - 7 - Question 11

The mass of the moon is 1/81 of the earth but the gravitational pull is 1/6 of the earth. It is due to the fact that

KEAM Paper 1 Mock Test - 7 - Question 12

The radiant energy from the sun incident normally at the surface of earth is 20 kcal/m2 min. What would have been the radiant energy incident normally on the earth, if the sun had a temperature twice of the present one

KEAM Paper 1 Mock Test - 7 - Question 13

A black body, at a temperature of 227ºC, radiates heat at a rate of 84 J-m⁻2-s⁻1. When its temperature is raised to 727ºC, the heat radiated by it in J-m⁻2-s⁻1 will be

KEAM Paper 1 Mock Test - 7 - Question 14

Two balls each of mass 60 g moving in opposite directions with speeds 4 m−s⁻1 collide and rebound with the same speed. The change in momentum will be

KEAM Paper 1 Mock Test - 7 - Question 15

A voltmeter of resistance 20000 Ω reads 5 volt. To make it read 20 volt, the extra resistance required is

KEAM Paper 1 Mock Test - 7 - Question 16

Thye position x of a particle varies with time, t, as x = at2-bt3. The acceleration of the particle will be zero at time t is equal to

KEAM Paper 1 Mock Test - 7 - Question 17

A particle is executing simple harmonic motion with an amplitude of 2 cm and angular frequency 100π rad-s⁻1. The maximum acceleration of the particle is

KEAM Paper 1 Mock Test - 7 - Question 18

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A):When a ball is thrown upwards, its momentum first decreases and then increases.
Reason(R):Law of conservation of momentum is not followed is this process.

KEAM Paper 1 Mock Test - 7 - Question 19

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Pressure in a bubble (σ) in an atmosphere of pressure P0 is   where r is the radius.
Reason(R): 4σ/r is the excess pressure due to two surfaces exposed to the atmosphere.

KEAM Paper 1 Mock Test - 7 - Question 20

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Gravitational field intensity at the centre of ring is zero.
Reason(R): Net force at the centre of ring is zero.

KEAM Paper 1 Mock Test - 7 - Question 21

Helium gas is filled in a closed vessel (whose coefficient of thermal expansion is negligible). When it is heated from 300 K to 600 K, then average kinetic energy of helium atoms will be

KEAM Paper 1 Mock Test - 7 - Question 22

A soap bubble (S.T.30 dyne/cm) has radius of 1 cm. The work done is doubling its radius would be

KEAM Paper 1 Mock Test - 7 - Question 23

A source and an observer move away in opposite directions with speed 10 ms-1, each with respect to ground. Apparent frequency is 1950 Hz. If velocity of sound is 340.5 ms-1, the natural frequency is

KEAM Paper 1 Mock Test - 7 - Question 24

A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of combination is

KEAM Paper 1 Mock Test - 7 - Question 25

An automobile engine develops 100 kW when rotating at a speed of 1800 rev-min⁻1. What torque does it deliver?

KEAM Paper 1 Mock Test - 7 - Question 26

The potential energy of a particle with displacement X is U(X). The motion is simple harmonic, when (K is a positive constant)

KEAM Paper 1 Mock Test - 7 - Question 27

Work done by 0.1 mole of a gas at 27ºC when it expands to double its volume at constant pressure is (assume R=2 cal mole-1 K-1)

KEAM Paper 1 Mock Test - 7 - Question 28

A copper block of mass 4 kg is heated in a furnance to a temperature 425ºC and then placed on a large ice block. The mass of ice that will melt in this process will be (Specific heat of copper=500 J-kg⁻1-ºC⁻1 and heat of fusion of ice = 336 kJ-kg⁻1).

KEAM Paper 1 Mock Test - 7 - Question 29

Length, breadth and thickness of a block of wood are measured and following results are obtained. These are l=(25.12 0.01) cm, b=(20.150.01)cm, t=(15.280.01) cm. The percentage error in the volume of the block is

KEAM Paper 1 Mock Test - 7 - Question 30

To demonstrate the phenomenon of interference we require two sources which emit radiations of

KEAM Paper 1 Mock Test - 7 - Question 31

The ratio of minimum to maximum wavelength in Balmer series is

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 31

From Bohr's theory for hydrogen atom

KEAM Paper 1 Mock Test - 7 - Question 32

In which of the following systems will the radius of the first orbit (n = 1) be minimum?

KEAM Paper 1 Mock Test - 7 - Question 33

Identify that set in which all the three sustances are good conductors of electricity

KEAM Paper 1 Mock Test - 7 - Question 34

The power of an electric bulb marked as 40 W and 200 V used in a circuit of supply voltage 100 V will be

KEAM Paper 1 Mock Test - 7 - Question 35

The curve drawn between velocity and frequency of photon in vacuum will be a

KEAM Paper 1 Mock Test - 7 - Question 36

When a charged oil drop moves upwards in an electric field, the electric force acting on the drop is

KEAM Paper 1 Mock Test - 7 - Question 37

Out of the folowing statement which is NOT true?

KEAM Paper 1 Mock Test - 7 - Question 38

A parallel plate capacitor is first charged and then a dielectric slab is introduced between the plates. The quantity that remains unchanged is

KEAM Paper 1 Mock Test - 7 - Question 39

A sheet of aluminium foil of negligible thickness is introduced between the plates of a capacitor. The capacitance of the capacitor

KEAM Paper 1 Mock Test - 7 - Question 40

Which of the following statements is true

KEAM Paper 1 Mock Test - 7 - Question 41

If radius of the earth contracted 2% and its mass remains the same then weight of the body at the earth surface

KEAM Paper 1 Mock Test - 7 - Question 42

On gradually, increasing the temperature of a substance, you will notice which of the following colour?

KEAM Paper 1 Mock Test - 7 - Question 43

On a cold morning, a metal surface will feel colder to touch than a wooden surface because

KEAM Paper 1 Mock Test - 7 - Question 44

A light string passing over a smooth light pulley connects two blocks of masses m₁ and m₂ (vertically). If the acceleration of the system is (g/8), then the ratio of masses is

KEAM Paper 1 Mock Test - 7 - Question 45

The electric current in a circular coil of two turns produced a magnetic induction of 0.2T at its centre. The coil is unwound and is rewound into a circular coil of four turns. The magnetic induction at the centre of the coil now is, in tesla (if same current flows in the coil)

KEAM Paper 1 Mock Test - 7 - Question 46

A body thrown with an initial speed of 96 ft/sec reaches the ground after (g=32 ft/sec2)

KEAM Paper 1 Mock Test - 7 - Question 47

A simple pendulum of length l has a bob of mass m, with a charge q on it. A vertical sheet of charge, with surface charge density σ passes through the point of suspension. At equilibrium, the spring makes an angle θ with the vertical. its time period oscillations is T in this poisiton. Then

KEAM Paper 1 Mock Test - 7 - Question 48

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): A ball of mass m fails from a height and bounces back to same height. Contact force is equal to rate of change of momentum.
Reason(R): Contact force is upwards.

KEAM Paper 1 Mock Test - 7 - Question 49

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): If velocity-time graph is a straight line parallel to time axis, then acceleration of body is zero.
Reason(R): Acceleration is equal to rate of change of velocity (constant).

KEAM Paper 1 Mock Test - 7 - Question 50

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Two blocks of masses m1 and m2 are at rest. They are moving towards each other under the mutual internal force. The velocity of centre of mass is zero.
Reason(R): If no external force acts on the system, then velocity of centre of mass is unchanged but can never be zero.

KEAM Paper 1 Mock Test - 7 - Question 51

In a plant a sucrose solution of coefficient of viscosity 0.0015 N s/m2 is driven at a velocity of 10⁻2m/s through xylem vessels of radius 2 μ m and length 5 μ m. The hydrostatic pressure difference across the length of xylem vessels, in N/m2 is

KEAM Paper 1 Mock Test - 7 - Question 52

When red glass is heated in dark room, it will seem

KEAM Paper 1 Mock Test - 7 - Question 53

An object of weight W and density ρ is submerged in a fluid of density ρ₁. Its appearent weight will be

KEAM Paper 1 Mock Test - 7 - Question 54

A mass M is moving with a constant velocity along a line parallel to x-axis. Its angular momentum with respect to origin or z-axis is

KEAM Paper 1 Mock Test - 7 - Question 55

Water falls from a height of 210 m. Assuming whole of energy due to fall is converted into heat the rise in temperature of water would be (J = 4.3 Joule/cal)

KEAM Paper 1 Mock Test - 7 - Question 56

Amplitude of vibration of any particle in a standing wave produced along a stretched string depends on

KEAM Paper 1 Mock Test - 7 - Question 57

A spring of force constant K is cut into two equal parts. Then the force constant of each piece is

KEAM Paper 1 Mock Test - 7 - Question 58

If the door of a refrigerator is kept open, then which of the following is true

KEAM Paper 1 Mock Test - 7 - Question 59

The difference in the lengths of a mean solar day and sidereal day is about

KEAM Paper 1 Mock Test - 7 - Question 60

Which one of the following properties of light does not support wave theory of light?

KEAM Paper 1 Mock Test - 7 - Question 61

The intermediate formed in the following reaction is-

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 61

The reaction is an example of cine subsitution or elimination addition

KEAM Paper 1 Mock Test - 7 - Question 62

The compound present in brorax bead is

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 62

This test is meant for detecting the coloured cations. When borax is heated on a platinum loop it swells up into a white porous mass first which on subsequent heating melts into a shining transparent glass bead (B2O3).

When this glass bead is heated with coloured compounds, a characteristic colour of metaborate is formed.

However, in a reducing flame, a different colour is obtained.

KEAM Paper 1 Mock Test - 7 - Question 63

The correct decreasing order of acidic nature is

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 63

Acidic character depends on stability of conjugate base. More stable conjugate base, more will be the acidic character

Electronegativity of Cl > Br > I So stability order of conjugate bases CIO- > BrO- > IO- Hence acidic character HCIO > HBrO > HIO

KEAM Paper 1 Mock Test - 7 - Question 64

In  the formal charge on each oxygen atom and P - 0 bond order respectively are

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 64

on exist ;n 4 resonating structures. Bond order of

3 negative charges of the ion is beings h are d by 4 oxygen atoms,
∴ formal charge on an O atom = -3/4

KEAM Paper 1 Mock Test - 7 - Question 65

Which one of the following compounds is not aromatic?

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 65

Aromaticity of a compound can be decided by Huckel's rule.
Huckel's rules are as follows:
1. Compound must be cyclic
2. The cyclic compound must have resonance and complete delocalization of electrons i.e., there must be conjugation.
3. The total number of pi electrons must fit the formula = 4n + 2, where n is a non - negative integer.
The important summary of this concept is as follows: (Remember this summary)

KEAM Paper 1 Mock Test - 7 - Question 66

The actinoids exhibit more number of oxidation states in general than the lanthanoids because

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 66

shielding effect of 5f < shielding effect of 4f
so Zeff (z effect) in actinoidis < Zeff (z effect) in lanthanoid
so extraction of electrons in actinoid is easy than lanthanoid which has 4f and better shielding.

KEAM Paper 1 Mock Test - 7 - Question 67

The compound when kept in pentane converts to a constitutional isomer. Identify that
isomer.

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 67

KEAM Paper 1 Mock Test - 7 - Question 68

The vapour pressure of water at 20 °C is 17.5 torr. What will be the no. of moles of water present in one litre of air at 20 °C and 40% relative humidity.(R =0.082 L atm/mol-k)

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 68

Relative humidity (RH) =
∴ Partial pressure of H2O = RH × Vapour pressure of H2O

KEAM Paper 1 Mock Test - 7 - Question 69

0.400 g of impure CaSO4 (Molar mass = 136) solution when treated with excess of barium chloride solution, gave 0.617 g of anhydrous BaSO4 (Molar mass = 233). The percentage of CaSO4 present in the sample is

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 69

KEAM Paper 1 Mock Test - 7 - Question 70

At temperature 300 K for reaction  C2H4(g) + 3O2(g)→ 2CO2(g) + 2H2O(l); ΔH = − 336.2 kcal. The approximate value of ΔU  at 300 K for the same reaction (R = 2 cal degree− 1 mol− 1) will be-

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 70

C2H4(g) + 3 O2(g)→2 CO2(g) + 2 H2O(l)
At 300 K ΔH = − 336.2 kcal
Δng = 2 − (1 + 3) = − 2
T = 300 K, ΔH = − 336.2 kcal,
R = 2 × 10−3 kcal degree−1 mol−1
ΔH = ΔU+ ΔngRT
− 336.2 = ΔU + (− 2) × 300 × 2 × 10−3
ΔU = − 336.2 + 1.2 = − 335.0 kcal

KEAM Paper 1 Mock Test - 7 - Question 71

The cations present in 'A'

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 71

KEAM Paper 1 Mock Test - 7 - Question 72

20 g helium is compressed isothermally and reversibly at 27 °C from a pressure of 2 atmosphere to 20 atmosphere. The change in the value of heat energy change during the process is (R = 2 cal kelvin-1 mol-1)

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 72

KEAM Paper 1 Mock Test - 7 - Question 73

Which of the following type of compound is used to increase the hardness of the silicone polymer.

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 73

Hydrolysis followed by condensation polymerization of RSiCl3 produces 3-D cross-linked silicones which are hard.

KEAM Paper 1 Mock Test - 7 - Question 74

Consider the reaction 2A + B →products, when the concentration of A alone was doubled, the half-life of the reaction did not change. When the concentration of B alone was doubled, the rate was not altered. The unit of rate constant for this reaction is

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 74

When concentration of B doubled rate does not changes
So,

Now when Concentration of A doubled half life does not change
it means reaction is first order so

order of reaction =1
so unit of rate constant = s -1

KEAM Paper 1 Mock Test - 7 - Question 75

The products A and B of the above reaction are respectively

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 75

KEAM Paper 1 Mock Test - 7 - Question 76

0.066 g of a metal was deposited when a current of 2 ampere passed for 100 seconds through an aqueous solution of its metal ion. The equivalent mass of the metal is-

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 76

Total charge passed in Coulombs = It = 2 X100 = 200 Coulombs
200 Coulombs of charge deposits 0.066 g of metal.
Equivalent mass of the metal is that mass of metal deposited by 1 Farad or 96500 Coulombs.
Equivalent mass of metal

KEAM Paper 1 Mock Test - 7 - Question 77

A mixture of gaseous nitrogen and gaseous hydrogen attains equilibrium with gaseous Ammonia according to the reaction

It is found that at equilibrium when temperature is 673 K , atmospheric pressure is 100, moles of gaseous nitrogen and gaseous hydrogen are in ratio 1:3 and mole percent of gaseous ammonia is 24 . The equilibrium constant Kp for the reaction at the above condition is-

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 77

Partial pressure of
=24.0 atm
Pressure of N2 + H2 = 100 – 24 = 76 atm
Partial pressure of
Partial pressure of N2

KEAM Paper 1 Mock Test - 7 - Question 78

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 78

KEAM Paper 1 Mock Test - 7 - Question 79

Study the following reactions and identify the reactant 'R'.

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 79

KEAM Paper 1 Mock Test - 7 - Question 80

A new carbon – carbon bond is formed in:

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 80

New carbon-carbon bond is formed is Friedal Craft reaction and Reimer-Teimann reaction
Friedal Craft’s reaction

Riemer Teimann Reaction

KEAM Paper 1 Mock Test - 7 - Question 81

The radiations from a naturally occurring radioactive substance, as seen after deflection by a magnetic field in one direction, are

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 81
Deflection in the magnetic field confirms that the particles are charged. It does not confirm the charge on the particles.

Hence, option (4) is correct.

α-rays consist of positively charged particles (He++) and β-rays consist of negatively charged particles . Since they are oppositely charged, so they get deflected in opposite directions. γ-rays are neutral (carry no charge). So, they remain undeflected.

KEAM Paper 1 Mock Test - 7 - Question 82

Both the molecules possess dipole moment in which of the following pairs?

Detailed Solution for KEAM Paper 1 Mock Test - 7 - Question 82

H2O and SO2 both possess dipole moment due to bent structure.

KEAM Paper 1 Mock Test - 7 - Question 83

Which of the following solutions will have pH close to 1.0?