Question # 1

The momentum of a particle is numerically equal to its K.E. What is the velocity of a particle?

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9 ms^-1

3 ms^-1

2 ms-1

1 ms^-1

Two charges of equal magnitudes and at a distance r exert a force F on each other. If the charges are halved and distance between them is doubled, then the new force acting on each charge is:

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F/8

F/4

F/16

4F

Rest mass energy of electron is:

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1.02 MeV

0.51 MeV

931 MeV

200 MeV

Photo cells are used for :

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Security and counting system

Automatic door system

Automatic street lighting

All of these

A machine gun fires ‘n’ bullets per second and the mass of each bullet is m. If v is the speed of each bullet then the force exerted on the machine gun is:

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mng

mnv

mnvg

mnv/g

A stone of mass 0.5kg tied with a string of length 1m is moving in a horizontal circle with a speed of 4ms-1 . The tension acting on the string in newton is:

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2

0.2

8

0.8

Two astronauts in a satellite must have

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Same masses

Same real weights

Same apparent weights

None of these

The maximum kinetic energy of emitted photoelectrons depends upon:

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The intensity of incident light

Frequency of the incident light

Temperature of the surface

All of above

When an electron in an atom goes from a lower to higher its:

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K.E. increases, P.E. decreases

K.E. increases

P.E increases

K.E. decrease, P.E. increases

The fundamental frequency of a closed organ pope is 50 Hz. The frequency ofsecond over tone is

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100hz

150hz

60hz

250hz

The mud flies off the tyre of a fast moving car in the direction

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parallel to the moving tyre

anti parallel to the moving tyre

tangent to the moving tyre

none of these

Light of frequency 2 times the threshold frequency is incident on the metalsurface. Ifthe frequency is by quartered and intensity is doubled, the photoelectric becomes

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Quadrupled

Zero

Doubled

Halved

A.H Compton studied the scattering of X-rays by loosely bound electrons from a graph target in:

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1905

1911

19251

1923

A total charge of 100C flows through 12W bulb in a time of 50 second. Which is the potential difference across the bulb during this time?

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0.12V

6.0V

2.0V

24V

The efficiency of a particle heat engine:

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can be 100%

Cannot be 100%

Is always zero

None of these

A man has weight 980 N in a stationary lift. What will be his weight if the lift starts moving up with anacceleration of 4.9 ms^-2

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980 N

1470 N

1980 N

1460 N

At constant temperature, if the volume of a given mass of a gas is doubled, then the density of gas becomes:

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Double

Remains constant

Half

None of these

The magnetic field of a solenoid is quite similar to that of a:

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Straight conductor

A horse shoe magne

Any magnet

A bar magnet

The specific resistance of a wire varies with its:

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Length

Cross-section

Mass

Material

In case of planets the necessary acceleration is provided by

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Gravitational force

coulomb force

frictional force

centripetal force

The phenomenon of radioactivity is associated with:

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Fission of nucleus

Disintegration of neutrons

Emission of spectral lines

Spontaneous disintegration of the nuclei of atoms

The diode charactristics curve is plot between

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I & t

V& t

V& I

None

A gas which strictly obeys the gas laws under all conditions of temperatures and pressure is called:

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Ideal gas

Inert gas

Real gas

None of these

Which one is the case when the wavelength is actually changed?

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When source move relative to observer

When observer move relative to source

When observer moves around a stationary source at the center of circle

When the relative displacement between source and observer is zero

The spectrum of a star’s light is measured and the wavelength of one of the lines as thesodium’s line is found to be 589 nm. The same line has the wavelength of 497 nm whenobserved in the laboratory. This means the star is

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Moving away from the earth

Moving towards the earth

Stationary

Revolving around the planet

At constant temperature, if the density of the gas is increased, its pressure will:

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Decrease

Increase

Remain unchanged

None of these

Due to emission of 𝖰+ − 𝒓𝒂𝒚𝒔:

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Mass of the nucleus increases

Mass of the nucleus decreases

Charge on the nucleus increases

Charge number decreases

In full wave rectification by bridge the number of diodes required are

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3

4

2

5

The equation PVr = Constant applies to:

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Isothermal process

Adiabatic process

Isobaric process

None of these

A 4 m long string fixed at its ends resonate in 4 segments. The wavelength of the waveis:

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4m

0.5m

2m

0.25 m

A whistle is revolved with high speed in a horizontal circle of radius R. to an observer at the centre of the circle the frequency of the whistle will appear to be:

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Decreasing

Increasing

Both

Constant

You lift a suit case from the floor and keep it on a table. The work done by you on the suitcase does not depend on

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the path taken by the suitcase

weight of the suitcase

initial and final position

None

In the theory of dimensional analysis, heat may be properly represented by:

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ML²T^-2

MT^-2

ML^-1T^-1

None of these

In Compton effect, it was considered that X-rays consist of:

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Electrons

Positrons

Photons

All of these

Half-life of radon gas is:

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1620 years

3.8 days

7 days

11 days

Petrol engine coverts ____________ of available heat energy into work.

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20% to 25%

25% to 30%

30% to 35%

35% to 40%

The only significant motion possessed by the mono-atomic gas molecules is:

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Translatory

Rotatory

Vibratory

None of these

Davisson and Germer received the Nobel prize for their work on:

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Wave nature of particle

Corpuscular nature of wave

Dual nature of particle

All of them

The ideal gas obey gas law at:

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Low tempratures and high pressures

High temperatures and low pressures

All temperatures and pressures

None of these

The magnitude of potential barrier for Ge is

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0.7 v

0.3 V

7v

3 v

Davisson and Germer, in their experiment used:

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Nickle crystal

Lead crystal

Graphite crystal

Glass