JEE Mains 2002

Select the correct statement.

When a covalent bond is formed, transfer of electrons takes place
Pure $H_{2} O$ does not contain any ion
A bond is formed when attractive forces overcome repulsive forces
$HF$ is less polar than $HBr$

Topic:

Chemical Bonding and Molecular Structure

Exam:

JEE Mains 2002

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Question 2

The number of lone pairs on

Xe

XeF_{2}

XeF_{4}

and

XeF_{6}

respectively, are

$3, 2, 1$
$2, 4, 6$
$1, 2, 3$
$6, 4, 2$

Topic:

Chemical Bonding and Molecular Structure

Exam:

JEE Mains 2002

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Question 3

Bond angle of

10 9^{\circ} 2 8^{'}

is found in

$NH_{3}$
$H_{2} O$
$C \oplus H_{5}$
$N H_{4} \oplus$

Topic:

Chemical Bonding and Molecular Structure

Exam:

JEE Mains 2002

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Question 4

A spring of force constant

800 N / m

has an extension of

5 cm

. The work done in extending it from

5 cm

15 cm

is
(a)

16 J

8 J

32 J

24 J

Topic:

Laws of motion

Exam:

JEE Mains 2002

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Question 5

Initial angular velocity of a circular disc of mass

M

ω_{1}

. Then, two small spheres of mass

m

are attached gently to two diametrically opposite points on the edge of the disc. What is the final angular velocity of the disc? (a)

(\frac{M + m}{M}) ω_{1}

(\frac{M + m}{m}) ω_{1}

(\frac{M}{M + 4 m}) ω_{1}

(\frac{M}{M + 2 m}) ω_{1}

Topic:

System of Particles and Rotational Motion

Exam:

JEE Mains 2002

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Question 6

A solid sphere, a hollow sphere and a ring are released from top of an inclined plane (frictionless), so that they slide down the plane. Then, maximum acceleration down the plane is for (no rolling)
(a) solid sphere
(b) hollow sphere
(c) ring
(d) All same

Topic:

System of Particles and Rotational Motion

Exam:

JEE Mains 2002

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Question 7

Energy required to move a body of mass

m

from an orbit of radius

2 R

3 R

is
(a)

\frac{GM m}{12 R ^{2}}

\frac{GM m}{3 R ^{2}}

\frac{GM m}{8 R}

\frac{GM m}{6 R}

Topic:

Gravitation

Exam:

JEE Mains 2002

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Question 8

The kinetic energy needed to project a body of mass

m

from the earth's surface (radius

R

) to infinity is
(a)

\frac{m g R}{2}

2 m g R

m g R

\frac{m g R}{4}

Topic:

Work, Energy and Power

Exam:

JEE Mains 2002

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Question 9

The escape velocity of a body depends upon mass as
(a)

m^{0}

m^{1}

m^{2}

m^{3}

Topic:

Gravitation

Exam:

JEE Mains 2002

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Question 10

If suddenly the gravitational force of attraction between earth and a satellite revolving around it becomes zero, then the satellite will
(a) continue to move in its orbit with same velocity
(b) move tangentially to the original orbit with the same velocity
(c) become stationary in its orbit
(d) move towards the earth

Topic:

Gravitation

Exam:

JEE Mains 2002

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Question 11

Two spheres of the same material have radii

1 m

and

4 m

and temperatures

4000 K

and

2000 K

, respectively. The ratio of the energy radiated per second by the first sphere to that by the second is
(a)

1 : 1

16 : 1

4 : 1

1 : 9

Topic:

Thermal properties of Matter

Exam:

JEE Mains 2002

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Question 12

If mass-energy equivalence is taken into account, when water is cooled to form ice, the mass of water should
(a) increase
(b) remain unchanged
(c) decrease
(d) first increase then decrease

Topic:

Thermal properties of Matter

Exam:

JEE Mains 2002

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Question 13

Which of the following is more close to a black body ?
(a) Black board paint
(b) Green leaves
(c) Black holes
(d) Red roses

Topic:

Thermal properties of Matter

Exam:

JEE Mains 2002

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Question 14

Infrared radiations are detected by
(a) spectrometer
(b) pyrometer
(c) nanometre
(d) photometer

Topic:

Electromagnetic Waves

Exam:

JEE Mains 2002

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Question 15

Heat given to a body which raises its temperature by

1^{\circ} C

is
(a) water equivalent
(b) thermal capacity
(c) specific heat
(d) temperature gradient

Topic:

Thermodynamics

Exam:

JEE Mains 2002

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Question 16

Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will
(a) increase
(b) decrease
(c) remain same
(d) decrease for some, while increase for others

Topic:

Thermal properties of Matter

Exam:

JEE Mains 2002

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Question 17

Even Carnot engine cannot give

100%

efficiency, because we cannot
(a) prevent radiation
(b) find ideal sources
(c) reach absolute zero temperature
(d) eliminate friction

Topic:

Thermodynamics

Exam:

JEE Mains 2002

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Question 18

Which statement is incorrect?
(a) All reversible cycles have same efficiency
(b) Reversible cycle has more efficiency than an irreversible one
(c) Carnot cycle is a reversible one
(d) Carnot cycle has the maximum efficiency in all cycles

Topic:

Thermodynamics

Exam:

JEE Mains 2002

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Question 19

for the resulting mixture is
(a)

1 mol

of a gas with

γ = \frac{7}{5}

is mixed with

1 mol

of a gas with

γ = \frac{5}{3}

, then the value of

γ

\frac{7}{5}

\frac{2}{5}

\frac{24}{16}

\frac{12}{7}

Topic:

Thermodynamics

Exam:

JEE Mains 2002

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Question 20

At what temperature is the rms velocity of a hydrogen molecule equal to that of an oxygen molecule at

4 7^{\circ} C

?
(a)

80 K

- 73 K

3 K