Question # 1

When the radioactive nucleus emits a beta particle, the proton neutron ration:

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increases by one

Remains same

Decreases by one

Decreases by four

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

An electron and a proton are accelerated through the same potential. If their masses are me and mp respectively, then the ratio of their de-Broglie wavelength is:

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1

mp/me

me/mp

Photoelectric effect and Compton effect prove the:

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Wave nature of light

Particle nature of light

Dual nature of light

Number of spark plugs needed in diesel engine is:

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Four

Five

Six

None of these

The photoelectric effect was explained by:

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Einstein

Davison

Hertz

Planck

The ratio of the SI unit to the C)G.S unit of torque is.

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10⁷

10⁹

10⁰

10³

. Time rate of change of momentum is equal to

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Force

Impulse

Velocity

Both A and C

A body of mass m tied to a string is moved in a vertical circle of radius r. the difference in tensions at the lowest point and the highest point is.

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2 mg

4 mg

6 𝑚g

8 mg

Hotness and coldness of an object is represented in terms of:

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Heat

Temperature

Chemicial

None of these

In which region of the electromagnetic spectrum does the Lyman series of hydrogen atom lie?

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Infrared

Visible

Ultraviolet

X-rays

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

Tick which of the following is not state variable:

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Heat energy

Pressure

Entropy

Volume

When passes from medium to another, deviate from its path is called

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reflection

refraction

diffraction

transmission

Which one is the correct express of de-Broglie equation for the length of atoms of mass m at temp? T(k=Boltzmann’s constant):

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For a particle in uniform circular motion the relation a = r 𝑎 of accelerations hold. The acceleration 'a'

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is centripetal acceleration

Is tangential acceleration

is radical acceleration

both A and B

Two projectiles ‘A’ and ‘B’ are thrown with same speed but at angle of 40 degree and 50 degree with the horizontal. The horizontal range of ‘A’ will be:

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Equal to that of ‘B’

Greater than that of ‘B’

Less than that of ‘B’

4/5times that of ‘B’

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

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 electron is a cathode-ray tube are accelerated from cathode to anode by a potential differenceof 2000 V. If this p.d is increased to 8000 V, the electrons will arrive at the anode with:

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Twice the kinetic energy and four times the velocity

Four times the kinetic energy and twice the velocity

Four times the kinetic energy and sixteen times the velocity

Sixteen times the kinetic energy and four times the velocity

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

Two 8 N forces act on each end of the beam of length 0.60m. Two forces are parallel and acting opposite to each other, the angle between the force and beam is 60o , what is the torque of the couple exerted on the beam:

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2.4 Nm

4.2 Nm

4.8 Nm

9.6 Nm

Thermal radiations are a type of:

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Mechanical waves

Electromagnetic waves

Alpha rays

Electrons

When a particle moves in a uniform circular motion. It has:

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Radial velocity and radial acceleration

Tangential velocity and radial acceleration

Tangential velocity and tangential acceleration

Radial velocity and tangential acceleration

A thorium nucleus is formed when a uranium nucleus emits an 𝑎 −particles. Atomic number of thorium is :

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23

60

90

70

The half-life of a radioactive element which has only 1//32 of its original mass left after a lapse of 60 days is:

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12days

10days

22days

36days

For a particle moving in uniform circular motion

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Velocity is transverse and acceleration is radical

Velocity is radial and acceleration is transverse

Both velocity and acceleration are radial

Both velocity and acceleration are transverse

When a dielectric is inserted between the plates of a capacitor, Which one is true

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Energy stored increase

Energy stored decrease

Capacitance decrease

All

In photoelectric effect, electrons are emitted:

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Slowly

Intermittently

Both (a) & (b)

Instantly

One degree of thermodynamics scale of temperature is called:

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Celsius

Fahrenheit

Kelvin

Radian

The rate of decay radioactive substance:

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Is constant

Decrease exponentially with time

Varies inversely with time

Decrease linearly with time

𝑎, 𝖰 𝒂𝒏𝒅 radiations come out of radioactive substance:

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Spontaneously

When it is put in a reactor

When it is heated

Under pressure

Which of the particles, electron, proton and neutron moving with same speed has longest wave length?

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Electron

Proton

Neutron

All have same

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%

de-Broglie wavelength associated with an electron moving at a speed of 1x106 ms-1 is

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4x10-10 ms-1

5x10-10 m

6x10-10 m

7x10-10 m

The angle of projection, at which the range of projectile would become half of its maximum value.

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45Degree

30Degree

15Degree

60 Degree

A body is moving in a circle with a constant speed. it has

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a constant velocity

a constant acceleration

a velocity of constant magnitude

an acceleration of constant magnitude

The distance between the plates of a charged parallel plate capacitor is 4mm and potential difference is 6 volts. If the distance between the plates is increased to 12mm, then :

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The potential difference of the capacitor will become 18 volts

The P.D become 20 volts

The P.D will remain unchanged

The charge on condenser will reduce to one third

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

In closed end organ pipe, the frequency of first harmonic is 300 Hz. The frequency ofthird overtone is :

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900 Hz

1500 Hz

2100 Hz

600 Hz

An electric room radiator, which operates at 50V has resistance of 50 Ω. Power of the radiator is approximately:

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100W

50W

450W

1000W