Question # 1

The potential difference applied to an X-rays tube is increased. As a result, in the emitted radiation

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The intensity increases

The minimum wavelength decrease

The intensity remains unchanged

Both B & C

Two astronauts in a satellite must have

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Same masses

Same real weights

Same apparent weights

None of these

A rider uses Motorcycle safety helmet that extends the time of collision during accident hence decreasing the

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Change of collisio

Force acting

Velocity

Impulse

Capacitor stores energy in the form of :

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Electric field

Both of these

Magnetic field

Gravitational field

A positively charged particle is moving perpendicular to a uniform magnetic field. The magnetic force makes the particle to move along:

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An elliptical path

A circular path

A parabolic path

None of these

The rate of change of momentum of a molecule is equal to:

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Pressure

Work

Density

Force

A magnetic field

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Always exerts a force on a charged particle

Never exerts a force on a charged particle

Exerts a force on a charged particle if it is moving across the magnetic lines of force

Exerts a force on a charged particle if it is moving along the magnetic lines of force.

What is the momentum of a photon of light of wavelength 500 nm in kgm/s:

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1.32 × 10−21

1.32 × 10−23

1.32 × 10−25

1.32 × 10−27

The coulomb’s law is valid for the charges which are:

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Moving and point charges

Stationary and point charges

Moving and non-point charges

Stationary and large size charges

A ball takes ‘t’ second to fall from a height 𝒉𝟏 and ‘2t’ second to fall from a height 𝒉𝟐 then h1/h2 is:

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2

4

0.5

0.25

The junction potential for Germanium is;

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3v

0.3 v

7v

0.7 v

Where in standing wave, do the vibrations of the medium occur?

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Only at the nodes

Only at the antinodes

At all points between the nodes

At all points between the antinodes

A long solenoid has 20 turns/ cm. The current necessary to produce a magnetic field of 20 mellites inside the solenoid is approximately:

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1A

2A

4A

8A

The temperature at which all the gases become liquid is called:

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273 K

-273 K

Absolute Zero

Both (B) and (C)

A body of mass m kg is lifted by a man to a height of one meter in 30 sec. Another man lifts the same mass to the same height in 60 sec. The work done by them are in the ratio

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1: 2

1: 1

2: 1

4: 1

Which of the following is not true?

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The Lyman series is a continuous spectrum

The Ballmer series is a line spectrum in the visible region

The Paschen series is a line spectrum in the infrared region

The spectral series formula can be derived from Rutherford’s model of the hydrogen atom 18. The photoelectric effect is the ejection of

Moving photons posses:

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Energy

Momentum

Wavelength

All of these

When a radioactive nucleus remits a beta particle, the proton neutron ratio:

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Decreases

Increases

Remain same

None of the above

Two bodies are projected at angles  and (90°–) with the horizontal at the same speed.The ratio of their maximum heights is

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1 : 1

1 : tan 

tan² : 1

A particle revolves round a circular path with a constant speed. The accelerationof the particle is

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A. A long the circumference of the circle

Along the tangent

Along the radius

Zero

In full wave rectification, the output DC voltage across the load is obtained for.

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The positive half cycle of input AC only

The negative half cycle of input AC

The completes cycle of input AC only

All of the above

A point on the rim of wheel 400 cm in diameter has a velocity of 1600 cms-1 . The angular velocity of the wheel is:

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6 rad/s

4 rad/s

2 rad/s

8 rad/s

If the tension in a string stretched between two fixed points is made four times, the frequency of the fundamental harmonic will become:

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Two times

Three times

Four times

Six times

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

In photo electric cell, the photo electric current

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Decreases with increase in frequency of light

Depends on intensity and frequency of light

Does not depend upon the frequency of light and but depends upon intensity of light

Increases with increase in frequency of light

The stopping potential for a certain metal is 10 volt, the max. Energy of emitted electron is:

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10 J

100 J

1.6 × 10-18 J

1.6 × 10-19 J

The efficiency of half wave rectifier is:

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25.6%

1.2%

40.6%

66.6%

The number of molecules in one mole of gas is equal to:

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Avogadro number N_A

Gas constant R

Boltzmann constant k

None of these

When heat is added to the system, the entropy change is:

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Positive

Negative

Zero

None of these

What is the resultant force in the diagram shown?

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Zero

6N to left

6N to right

11N to right

Wavelength of the wave is the distance between the particles of the medium having adifference of:

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Zero

n

2n

𝜋2

In order to increase the K.E of ejected photo electrons, there should be an increase in:

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Intensity of radiation

NoneI

Frequency of radiation

Both (b) & (c)

The more readily fissionable isotope of uranium has an atomic mass of:

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220

230

235

240

A man M₁ of mass 80 kg runs up a staircase in 15s. Another man M₂ also of mass 80 kg runs up the same staircase in 20s. The ratio of the power developed by them will be

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1

4/3

16/9

none of these

Diesel 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 rate of decay radioactive substance:

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Is constant

Decrease exponentially with time

Varies inversely with time

Decrease linearly with time

Ratio of dimension of K.E and power is:

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1:1

T:1

1:T

M:J

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

Figure represents a graph of kinetic energy (K) of the photoelectrons (in eV) and frequency (v) for a metal used as cathode in photoelectric experiment. The work function of metal is:

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1 eV

2 eV

1.5 eV

3 eV

Two railway trucks of masses m and 3m move towards each other in opposite directions with speeds 2v and v respectively. These trucks collide and stick together. What is the speed of the trucks after the collision?

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v/4

v/2

v

5v/4

The time taken by an engine of power 10 kW to lift a mass of 200 kg to a heightof 40 m is (g + 10ms2)

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2 sec

4 sec

8 sec

16sec