Question # 1

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

In an ideal gas, the molecules have:

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Kinetic energy only

Potential energy only

Both KE and PE

None of these

A particle is moving with constant speed by keeping itself at constant distance from a fixed point in a given plane. Its motion is

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Circular motion

Uniform circular motion

Uniform circular motion with fixed axis of rotation

Uniform circular motion with axis of rotation not defined

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

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

Davisson and Germer, in their experiment used:

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Nickle crystal

Lead crystal

Graphite crystal

Glass

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

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

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reflection

refraction

diffraction

transmission

Threshold wavelength for metal having work function 𝝋 is 𝝀. What is the threshold wavelength for metal having work function 2 𝒊𝒔:

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/𝟐

2

4

𝝀/𝟒

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%

If the radius of the circular path of particle going around the circle is doubled without changing its frequency of rotation, then centripetal force on it is.

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doubled

halved

unchanged

quadrupled

When a person lifts a body from ground work done by lifting force is?

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Positive

Negative

Zero

Half of positive maximum

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

The efficiency of a particle heat engine:

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can be 100%

Cannot be 100%

Is always zero

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

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

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3

4

2

5

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the Stopping distance will be:

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The same

Doubled

Halved

Four times

No entropy change is associated with:

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Isothermal

Adiabatic process

Isobaric process

None of them

If the magnitude of charge on each of two objects is doubled and the distance between them is also doubled then force between them:

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Doubled

Quadrupled

Halved

Remains same

An elevator's motor produces 3000 W power. The speed With Which it can lift a 1000 kg load is:

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30.6ms^-1

0.306ms^-1

3.06ms^-1

300.3ms^-1

Interference and diffraction of light confirms its:

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Particle nature

Dual nature

Wave nature

Electromagnetic nature

The rate at which the battery is supplying the electrical energy is the:

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Power output

Electrical power

Power input

Both A and C

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

During a negative β-decay

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An atomic electron is ejected

A neutron in the nucleus decays emitting an electron

An electron which already present within the nucleus is ejected

A part of binding energy of nuclei is converted into electron

Which of the Following bulb will glow Brightest?

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100W

200W

300W

400W

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

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

Half-life of radon gas is:

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1620 years

3.8 days

7 days

11 days

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

The nature of thermal radiation is smaller to:

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Ultraviolet rays

Light rays

Both of them

None of these

electrons from the surface of a metal when:

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It is heated to a high temperature

Radiation of suitable wavelength falls on it

Electrons of suitable velocity strike it

It is placed in a strong electric field

In a photocell, sodium and potassium emit electrons for:

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Visible light

Infrared light

Ultraviolet light

All of these

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

Potassium cathode in photocell emits electrons for a light:

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Visible

Infrared

Ultraviolet

X-rays

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

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 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

If P is the pressure and V is the volume, Then PV will represent:

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Power

Work

Force

None of these

If the range of a projectile is R, the potential energy will be maximum after the projectile has covered (from start) distance equal to:

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R/2

R/4

R

R/9

A certain engine coverts 20% of available heat energy into work. Then its efficiency will be:

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20%

80%

50%

None of these

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