Question # 1

The momentum of the moving photon is:

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Zero

ℎ

𝜆

ℎ𝜆

As in linear motion force determines linear acceleration where as in circular motion torque determines its

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Angular acceleration

Linear acceleration

Vibratory acceleration

Tangential acceleration

A straight current carrying conductor experiences maximum forces in a uniform magnetic field when it is placed:

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Parallel to the field

Perpendicular o the field

At an angle of 45 to the field

None of these

A satellite moving round the earth constitute

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An inertial frame of reference

Non inertial frame

Neither inertial nor non inertial

Both inertial and non-inertial

The uranium Nucleus 𝟐𝟑𝟖 𝑼 undergoes successive decays, emitting respectively 𝑎 − 𝒓𝒂𝒚,𝖰 − 𝒓𝒂𝒚 𝒂𝒏𝒅 − 𝒓𝒂𝒚𝒔. What is the atomic number and atomic mass of the resulting nucleus:

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90, 238

91, 234

92, 236

92, 238

Which row is correct for fission and for fusion?

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Produces larger nuclei

Produces smaller nuclei

The efficiency of full wave rectifier is:

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25.6%

81.2%

81.6%

71.2%

The relationship between Boltzmann constant K with R and N_Ais given as:

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k = RN_A

k = R/N_A

k = NR/N_A

None of these

The time of flight of a projectile is maximum when angle of projection is:

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30 Degree

45Degree

60Degree

90Degree

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

The energy of photon of energy 1 eV is:

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1240 nm

1040 nm

1000 nm

620 nm

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

If a car moves with a uniform speed of 2 ms-1 in a circle of radius 0.4m. Its angular speed is

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4 rad. s^-1

1.6 rad. s^-1

5 rad. s^-1

2.8 ms^-1

According to Bohr’s theory, a line in the Ballmer series arises when the electron jumps from any of the higher orbits to the orbit with quantum number:

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1

2

3

4

What will be efficiency of carnot engine when it is operated between the temperatures 47^oC and 127 ^oC:

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Reversible

Irreversible

Sometimes A and B

None of these

A longitudinal sinusoidal wave has wavelength of 1cm and a period of 2sec. Its wavevelocity is:

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50 cm/ sec

0.5 cm/ sec

5 m/ s

0.005 m/ sec

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%

At the highest point on the trajectory of a projectile, its

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Potential energy is minimum

Kinetic energy is maximum

Total energy is maximum

Kinetic energy is minimum

Nuclear fission experiments show that the neutrons the uranium nuclei into two fragment of about the same size. This process is accompanied by the emission of several:

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Protons and positrons

𝛼 −partilces

neutrons

Protons and 𝛼 −partilces

The ‘emf ’ is always even when no current is drawn through the battery of the cell:

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Zero

Present

Absent

Maximum

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

Light of frequency 1.5 times the threshold frequency is incident on a photo sensitive material. If the frequency is halved and intensity is doubled the photo electric current becomes

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Four times

Half

Double

Zero

G.P Thomson revealed:

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Particle nature of electron

Dual nature of electron

Wave nature of electron

Electromagnetic nature of electron

A proton, accelerated through a p.d V has a certain de Broglie wavelength. In order to have the same de Broglie wavelength, an 𝑎 −particles must be accelerated through a potential difference:

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4V

8V

V/4

V/8

The motion of molecules in gases i:

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Orderly

Random

Circular

All of these

Photoelectric effect and Compton effect prove the:

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Wave nature of light

Particle nature of light

Dual nature of light

When a radioactive nucleus emits a 𝖰 −paritcles, the mass number of the atom:

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Increases by one

Decreases by one

Remains the same

Decreases by four

Avogadro number is known as number of molecules in:

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One kg of a substance

Unit volume of a substance

One mole of a substance

None of these

J.J Thomson finds:

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Particle nature of the electron

Dual nature of electron

Wave nature of electron

Electromagnetic nature of electron

A cell of negligible resistance and e.m.f 2 V is connected across a series combination of 2,3 and 5 ohms. The p.d. across the 3 Ω resistor is

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0.6 V

1/3 V

2/3 V

4/3 V

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

When an observer moves towards a stationary source with a speed equal to 1/5 timesof speed of sound, the percentage increase in the frequency of sound is:

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20%

40%

5%

10%

Work function of all metals varies from 2 eV to 4eV. It is 4.2 eV for Aluminum and2eV for Sodium. If these two metals are illuminated by same light, the thresholdfrequency ofAluminum is

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Less than Sodium

Equal to that of Sodium

Grater than Sodium

Can’t be decided

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

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Decreases

Increases

Remain same

None of the above

In uniform circular motion, the factor that remains constant is:

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Linear velocity

Acceleration

Speed

All of these

When the velocity of a body is doubled:

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Its K.E is doubled

Its P.E is doubled

Its momentum is doubled

Its acceleration is doubled

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

The direction of force experienced by a moving in a magnetic field will be:

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Parallel to the field

Opposite to the field

Parallel to its direction of motion

Perpendicular to both the field and the velocity vector

The power needed to lift amass of 5000g to height of 1min 2 second is

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2.45 watt

24.5 watt

245 watt

2.45 k watt

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

The energy of photon of wavelength 1240 nm is:

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0.5 eV

1.0 eV

1.5 eV

2.0 eV