Question # 1

Which of the following is a unit of energy?

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unit

whatt

Horse Power

None of the above

As the intensity of incident light increases:

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Photoelectric current increases

Photoelectric current decreases

Kinetic energy of emitted photoelectrons increases

Kinetic energy of emitted photoelectrons decreases

The fusion of hydrogen into helium is more likely to take place:

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At high temperature and high pressure

At high temperature and low pressure

At low temperature and low pressure

At low temperature and high pressure

A wave which consists of a single, non-repetitive disturbance is called a

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Continuous wave

Longitudinal wave

Pulse

Transverse wave

In thermodynamics, the change in internal energy depends upon:

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The path taken between initial and final states

The initial state only

The final state only

Initial and final states

The unit Compton wavelength is same as:

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Compton wavelength

Compton frequency

Compton shift

Both (a) & (b)

The angular analogue of linear displacement is called

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angular velocity

angular displacement

angular momentum

moment of force

The force which provides the necessary centripetal force to keep the mud in circular path is called

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cohesive force

adhesive force

frictional force

gravitational force

The example of nuclear fusion is:

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Formation of barium and krypton from uranium

Formation of plutonium -235 from uranium -235

Formation of helium from hydrogen

Formation of water from hydrogen and oxygen

The frequency and work function of an incident photon are n and𝝋𝟎. If f0 is the threshold frequency, then necessary condition for the emission of photo electron is:

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< 𝑓0

𝑓 ≥ 𝑓0

f = 𝑓0/2

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

Thermal radiations are a type of:

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Mechanical waves

Electromagnetic waves

Alpha rays

Electrons

Vertical component of velocity of the projectile at any instant ‘t’ from the ground is given by:

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𝑣𝑖𝑐𝑜𝑠𝜃

𝑣𝑖𝑐𝑜𝑠𝜃 − 𝑔t

𝑣𝑖𝑠𝑖𝑛𝜃 − 𝑔t

𝑣𝑖𝑠𝑖𝑛𝜃 + 𝑔t

The body at rest may have:

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Energy

Momentum

Speed

Velocity

A monkey is accelerating down a string whose breaking strength is two third of his weight. The minimumacceleration of the monkey should be

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1/3g

g

2/3 g

0 m/s2

The maximum energy of the photoelectrons can be determined by making the:

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Anode positive

Anode negative

Cathode positive

Both (b) & (c)

Charge to mass ratio (e/m) of a charge particle is also called its:

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Specific charge

Specific Force

Gyro-magnetic ratio

Magneto-mechanical ratio

When ultraviolet rays are incident in metal plate, then photoelectric effect does not occur. It occurs by the incidence of:

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x-rays

Infrared rays

Radio wave

Greenhouse effect

Three quarks make up a:

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Leptons

Mesons

Baryons

Quark

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

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

If a body changes its momentum from 100 N s to 200 N s in 10 s then the unbalanceexternal force responsible to change the momentum is

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5 N

2.5 N

2n

10n

Temperature of black body radiating at 270c is increased to 327oc, then emittedenergywill increase by

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2 times

12 times

16 times

4 times

A 50 kg man with 20 kg load on his head climbs up 20 steps of 0.25 m height each. The work done in climbing is

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5 J

350 J

100 J

3430 J

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

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Electrons

Positrons

Photons

All of these

Which statement about geostationary orbit is false?

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A geostationary orbit must be directly above the equator

All satellite in a geostationary orbit must have the same masses

The period of geostationary orbit must be 24 hours

There is only one possible radius for a geostationary

The magnetic field produced due to the current in a straight wire is proportionalto the :

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Electric current

Conducting material

Length of the wire

Diameter of the wire

The emf of a cell of negligible internal resistance is 2V. It is connected to the series combination of 𝟐𝛀, 𝟑𝛀 𝐚𝐧𝐝 𝟓𝛀 resistance. The potential difference across 𝟑𝛀 resistance will be in volt:

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0.6

2/3

3

6

In nuclear fission reaction, when the products are 140X and 94Sr, the number of neutrons emitted is

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1

2

5

9

The potential difference between head and tail of an "electric eel" can be upto.

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6V

60V

6000V

600V

A body revolved around the sun 27 times faster then the earth what is the ratioof their radii

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1/27

1/4

1/9

1/3

A diode as a rectifier converts:

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A)c into D)c

D)c into A)c

Varying D)c current into constant D)c current

High voltage into low voltage and vice-versa

Photoelectric effect and Compton effect prove the:

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Wave nature of light

Particle nature of light

Dual nature of light

A progressive sound wave is a means of transferring energy. A progressive sound waveof constant frequency is generated in air. The intensity of energy transfer is directlyproportional to another of the wave parameters. Which of the following is correct?

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Intensity 𝖺 (𝑎𝑚𝑝𝑙𝑖𝑡𝑢𝑑𝑒)²

Intensity 𝖺 (𝑝𝑒𝑟𝑖𝑜𝑑𝑖𝑐 𝑡𝑖𝑚𝑒)²

Intensity 𝖺 (𝑠𝑝𝑒𝑒𝑑)²

Intensity 𝖺 (𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ)²

For X-rays which of the following is not correct:

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Cause of ionization in air when they pass through it

Can be deflected by electric and magnetic fields

Can be used to detect flaws in metal casting

Travel with the speed of light

The diodes works on

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A.C

D.C

both A and B

None of these

Pressure may be defined as_____per second per unit area:

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Change in force

Change in momentum

Change in energy

Work done

The rate of change of momentum of a body falling freely under gravity is equal to its

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Impulse

Kinetic energy

Pover

Weight

The unit of work function is

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eV

Volt

Farad

Herdz

In the absence of air resistance, a stone is thrown from P and follows a parabolic path in which the highest point reached is T. The vertical component of acceleration of stone is:

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Zero at T

Greatest at T

) Greatest at P

the same at P as at T

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