Online Test

Question # 1

If S is the stress and Y is Young's modulus of the material of a wire, the energy stored in the wire per unit volume is

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2 S²Y

S²/2Y

2Y/S²

S/2Y

The unit of intensity level of sound is

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watt

joule

bel

sabin

The mks unit of Mechanical Equivalent of heat is

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Joulex calorie

Joule/ calorie

Calorie x erg

erg/ calorie

The process of scattering of an x-ray photon by an electron is called

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Compton Effect

Photoelectric Effect

Pair Production

Annihilation

In the stress-strain graph stress is increased linearly with strain until a point is reached this point is known as

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Plastic limit

Plastic deformation

Proportional limit

Elastic behaviour

The approximate efficiency of silicon solar cell is

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5 - 10 %

9 - 12 %

12 - 16 %

15 - 18 %

The terminal velocity of falling object will be proportional to

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r²

1/r²

r

1/r

An optical fibre with its protective case may be typically 6.0 mm in diameter and yet it can replace bundle of copper of diameter

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6.79 cm

6.95 cm

7.52 cm

7.62 cm

1 joule is equal to electrons volt

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1.6 x 10^-19

1.6 x 10¹⁹

6.25 x 10¹⁹

6.25 x 10¹⁸

A capacitor of 2μF is connected with a battery of 12 volts the charge stored is

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2.5 × 10^-5 C

2.4 × 10^-6 C

2.4 × 10^-5 C

2.4 × 10^-6 C

The ratio of stress/strain is called as

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Modulus of elasticity

Bulk modulus

Shear modulus

Young's modulus

In LCR circuit which one of the following statements is correct?

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L and R oppose each other

R value increase with frequency

The inductive reactance increases with frequency

The capacitive reactance increases with frequency

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Work

Pressure

Momentum

Power

Pressure of a gas at constant volume is proportion to

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Total energy of gas

Average P.E of molecules

Average K.E of molecules

Total internal energy of gas

A spectrometer is used to find

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Wavelength of light

Refractive index of the prism

Angle of minimum deviation of prism

All of these

Base quantities are

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Scalars

Vectors

Both

None of these

Swinging pendulum eventually stop because of its energy is

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Destroyed

Converted into K.E

Converted into P.E

Converted into heat energy

A piece of wire along which charges are made to accelerate is known as

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Transmitting antenna

Receiving antenna

Modulator

Nor of these

The value of current gain of n-p-n transistor is of the order of

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tens

hundreds

thousands

ten thousands

There will be no change in _______ of light entering glass

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Velocity

Frequency

Direction

Wavelength

If a magnet is broken into two pieces, then

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Two magnets are obtained

North pole is obtained

South pole is obtained

One North Pole and one South Pole is obtained

A body falling freely under the action of gravity has

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Constant weight

Variable weigth

Maximum weigth

No weigth

When a semiconductor is continuously heated then value of its resistance

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Increases

Decreases

Decreases and then increases

Remains unchanged

Geometrical optics cannot give following characteristics for a microscope

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Image position

Image size

Resolution of image

Any of the above

Two sources of sound are said to be coherent if

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They produce sounds of equal intensity

They produce sounds of equal frequency

They produce sound waves vibrating with the same phase

They produce sound waves with zero or constant phase difference all instant of time

The approximate efficiency of liquid fuel rocket is

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49%

50%

48%

47%

The Earth's potential is considered to be at

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Zero

Minimum

Maximum

Infinite

The resistivity decrease with the increase of temperature of

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Gold

Silver

Copper

Silicon

The safe equivalent dose for workers for a week in the nuclear facilities or mines is

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3 m SV

1 m SV

0.5 m SV

None of these

In multimode graded index fibre core and cladding has boundary

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Noticeable

No noticeable

No boundary

None of these

The terms phase difference and path difference are:

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Same

Different

Equal

None of these

The waves which propagate by the oscillation of material particles are known as

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Water waves

Electromagnetic waves

Mechanical waves

None of these

A charge particle when projected perpendicular to the direction of the field experience a

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Minimum force

Maximum force

No force

None of these

The ratio of fringes with for bright and dark fringes is

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1 : 2

2 : 1

1 : 4

1 : 1

As a wave progressive, each point in the medium oscillates with the

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smaller frequency and same period of the source

same frequency and smaller period of the source

same frequency and period of the source

all of them

Which particle has the greatest relative biological?

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neutron

β-particle

α-particle

X-ray

In physics, the term "work" involves the

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force only

displacement only

force as well as displacement

none of them

The impedance of the series circuit at resonance frequency is

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Minimum

Maximum

Zero

1

The smallest portion of a crystal lattice that if repeated in three-dimensions will generate the entire lattice is called:

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Unit cell

Lattice plane

Crystal

None of these

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

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Positive

Negative

Zero

None of these

The speed of light in vacuum or in air is

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3 x 10¹⁰ m ! s

3 x 10⁹ m ! s

3 x 10⁸ m ! s

3 x 10⁷ m ! s