Online Test

Question # 1

Due to collisions of electrons, with the atoms of conductor, the energy transfer ultimately to the

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Atoms

Electrons

Lattice

All of them

If a train traveling at 72 kmph is to be brought to rest in a distance of 200 meters,then its retardation should be

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20 ms^-2

10 ms^-2

2 ms^-2

1 ms^-2

If two waves of length 50 cm and 51 cm produced 12 beats per second the velocity of sound is

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360 m/s

306 m/s

331 m/s

340 m/s

If 42 J heat is transferred to the system and the work done by the system is 32 J, then what will be the change in internal energy?

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0 J

2 J

5 J

10 J

The radioactive remnant materials can not be disposed of like

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Dumped into oceans

Soil

Air

All of them

The phenomenon is found to be prominent when size of the opening (aperture) is

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Grater than wavelength of light

Smaller than wavelength of light

Equal of light used

None of these

The product of force and time of impact force is called

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Momentum

Impulsive force

Impulse

Rate of change of momentum

Two bodies of masses m₁ and m₂ have equal momentum their kinetic energies E₁ and E₂ are in the ratio

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√m₁ : √m₂

m₁ : m₂

m₂ : m₁

m²₁ : m²₂

X-rays photons absorb in tissues and break molecular bonds and create

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Atoms

Free radicals

Highly reactive radicals

None of these

The C.R.O. is used displaying the waveform of a given

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Current

Frequency

Voltage

None of these

When a body moves with increasing acceleration, its velocity-time graph is a

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straight line

horizontal straight line

vertical straight line

curve

If 40 waves pass through the medium in 1 second with speed of 20 ms^-1then the wave length is

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0.5 m

1 m

2 m

2.5 m

A body is floating in a liquid the up thrust on the body is

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Equal to weight of liquid displaced

Zero

Less than the weight of liquid displaced

Weight of body-weight of liquid displaced

After break down the reverse current will rise to

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Small value

High value

Very high value

None of these

What is the time taken by light to travel 4 mm in a material of refractive index 3

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4 x 10^-11 s

2 x 10^-11 s

16 x 10^-11 s

8 x 10^-11 s

The value of young's modulus is maximum for:

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Dimond

Copper

Ice

Mercury

Water

The diameter of an atom is of the order of

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10^-125m

10^-11m

10^-10m

10^-9m

In integers such as 8,000 Kg, significant zeros are determined by the instrument when least count is 1 Kg

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8.00 × 10³ Kg

8.000 × 10³ Kg

8.00 × 10³ Kg

8.0 × 10³ Kg

Only those processes are probable to take place for which entropy os the system:

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Increases

Remains constant

Both A and B are correct

None of above

A force applied on a body produces acceleration in

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Its opposite direction

Its own direction

Right angle to the force

None of these

If a transverse wave travelling in a rare medium is incident on a denser medium, it is reflected such that it undergoes a change of

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0°

90°

135°

180°

Which of the following processes will result into fission reaction?

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₉₂U²³⁵ is bombarded with fast moving neutrons

₉₂U²³⁵ is bombarded with thermal neutrons

U²³⁸ is bombarded with slow moving neutrons

U235 being unstable breaks into smaller fragments

The dimensions of velocity are

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[ LT ]

[ LT²]

[ LT^-1]

[ LT^-2]

The diameter of the milky way is

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10¹⁵ m

10¹⁷ m

10¹⁸ m

10²⁰ m

In R.L.C. parallel circuit at resonance

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X_R = X_c

X_L = X_c

X_R = X_L

None of these

Which of the following particle emit with same energy from nucleus

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α-particle

β-particle

γ-particle

None of these

The relation E = σT⁴ represents

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Wein's Law

Stefen's Law

Stefen Boltzman Law

None of these

The equation of the displacement of a body executing S.H.M is x = x_∘cosω t. What is initial phase

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0°

90°

180°

270°

The effect of loading the prongs of a tuning fork with wax is to:

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Increase the frequency

Decrease the frequency

Maintain the original frequency

All of these

If a nucleus emits an alpha particle, its mass number decreases by 4 while charge number decreases by

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-4

4

2

1

A container has a small hole in the bottom.Air can go through this hole,but water cannot,this can be best explained by the statement that

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Water contains hydrogen atoms,air does not

Water molecules are larger than molecules in the air

Water molecules are smaller than molecules in the air

Surface tension of the water prevents it from

On increasing the length of a second s pendulum by z% its time period will

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Increase by 2 Z%

Decrease by z%

Decrease by 2 z%

Increase by 0.5 z%

An example of a photoconductor is:

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Boron

Carbon

Iron

Aluminum

Selenium

The fundamental quantities which form the base for the SI systems are:

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Mass, energy and time

Mass, force and time

Mass, length and time

Force, length and time

X-rays can penetrate into a solid matter upto

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Few millimeter

Several millimeter

Few centimeter

Several centimeter

The siemens is the SI unit of

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Resistance

Specific Resistance

Conductance

Inductance

The potential difference across the depletion of region of germanium is

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0.3 V

0.4 V

0.8 V

0.9 V

When some compass needless are placed on a card board along a circle with the center at the wire, they will:

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Point in the direction of N-S

Set themselves tangential to the circle

Point in the direction of E-W

Point in the direction of S-E

None of these

Speed of light in vacuum is

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0 ms^-1

3 x 10⁸ms^-1

1.5 x 10⁸ms^-1

None of these

Analyzer is use to

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Polarize the light

Un-polarize the light

Check whether the light is polarized or un polarized

Rotate the plane of polarized light

In an electron microscope, the electrons are accelerated to high energies by applying voltage

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30 kV to several mega volt

20 kV to several volts

23 kV to several volt

None of these