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KVPY Aptitude Test - Stream SX

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We consider the Thomson model of the hydrogen atom in which the proton charge is distributed uniformly over a spherical volume of radius $0.25$ Angstrom. Applying the Bohr condition in this model the ground state energy (in $eV$ ) of the electron will be close to

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Important Questions on KVPY PROBLEMS 2019 STREAM - SX

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KVPY Aptitude Test - Stream SX

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 14 - KVPY PROBLEMS 2019 STREAM - SX>PHYSICS>Q 3

A spherical rigid ball is released from rest and starts rolling down an inclined plane from height $h = 7 m,$ as shown in the figure. It hits a block at rest on the horizontal plane (assume elastic collision). If the mass of both the ball and the block is $m$ and the ball is rolling without sliding, then the speed of the block after collision is close to

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(take $g = 10 m s^{- 2}$ )

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 14 - KVPY PROBLEMS 2019 STREAM - SX>PHYSICS>Q 4

A girl drops an apple from the window of a train which is moving on a straight track with speed increasing with a constant rate. The trajectory of the falling apple as seen by the girls is

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 14 - KVPY PROBLEMS 2019 STREAM - SX>PHYSICS>Q 5

A train is moving slowly at

2 m s^{- 1}

next to a railway platform. A man,

1.5 m

tall, alights from the train such that his feet are fixed on the ground. Taking him to be a rigid body, the instantaneous angular velocity (in

rad s^{- 1}

) is

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 14 - KVPY PROBLEMS 2019 STREAM - SX>PHYSICS>Q 6

A point mass

M

moving with a certain velocity collides with a stationary point mass

\frac{M}{2}

. The collision is elastic and in one dimension. Let the ratio of the final velocities of

M

and

\frac{M}{2}

x .

The value of

x

HARD

KVPY Aptitude Test - Stream SX

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 14 - KVPY PROBLEMS 2019 STREAM - SX>PHYSICS>Q 7

A particle of mass

\frac{2}{3} kg

with velocity

v = - 15 m s^{- 1}

t = - 2 s

is acted upon by a force

f = k - β t^{2}

(in

N

). Here

k = 8 N

and

β = 2 N s^{- 2}

. The motion is one dimensional. Then the speed at which the particle acceleration is zero again, is

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 14 - KVPY PROBLEMS 2019 STREAM - SX>PHYSICS>Q 8

A certain stellar body has radius

50 R_{s}

and temperature

2 T_{s}

and is at a distance of

2 \times 10^{10} A . U .

from the earth. Here

A . U .

refers to the earth Sun distance and

R_{s}

and

T_{s}

refer to the Sun's radius and temperature respectively. Take both star and Sun to be ideal black bodies. The ratio of the power received on earth from the stellar body as compared to that received from the Sun is close to

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 14 - KVPY PROBLEMS 2019 STREAM - SX>PHYSICS>Q 9

As shown in the schematic below, a rod of uniform cross-sectional area $A$ and length $l$ is carrying a constant current $i$ through it and voltage across the rod is measured using an ideal voltmeter. The rod is stretched by the application of a force $F$ . Which of the following graphs would show the variation in the voltage across the rod as function of the strain, $ε$ , when the strain is small. Neglect Joule heating.

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 14 - KVPY PROBLEMS 2019 STREAM - SX>PHYSICS>Q 10

Two identical coherent sound sources

R

and

S

with frequency

f

are

5 m

apart. An observer standing equidistant from the sources and at a perpendicular distance of

12 m

from the line

R S

hears maximum sound intensity. When he moves parallel to

R S

the sound intensity varies and is a minimum when he comes directly in front of one of the two sources. Then a possible value of

f

is close to (the speed of sound is

330 m s^{- 1}

)

We consider the Thomson model of the hydrogen atom in which the proton charge is distributed uniformly over a spherical volume of radius 0.25 Angstrom. Applying the Bohr condition in this model the ground state energy (in eV) of the electron will be close to

Important Questions on KVPY PROBLEMS 2019 STREAM - SX

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We consider the Thomson model of the hydrogen atom in which the proton charge is distributed uniformly over a spherical volume of radius $0.25$ Angstrom. Applying the Bohr condition in this model the ground state energy (in $eV$ ) of the electron will be close to